I  B  RA  R.Y 
OF  THE. 
U  N  I  VERS  ITY 
Of  ILLINOIS 


621.11 

R68e 
1892 


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0 


OPINIONS  OF  THE  PKESS. 


The  Manufacturer  and  Builder,  New  York. 

An  Engineer's  Handy-Book. — Mr.  Roper,  the  writer  of  this  work,  is  well 
known  to  many  of  our  readers  as  the  author  of  a  number  of  useful  reference 
books  relating  to  steam-engineering,  which  have  become  deservedly  popular  by 
reason  of  their  plain  and  intelligibie  style  and  their  freedom  from  unnecessary 
*  and  confusing  mathematical  technicalities.  Mr.  Roper's  object  in  all  these  hand- 
books has  avowedly  been  to  present  facts  and  explain  principles  in  language  so 
plain  and  comprehensible  that  average  steam-users,  engineers,  firemen,  and 
those  who  are  usually  found  in  charge  of  steam-machinery,  can  read  his  books 
understandingly  and  with  profit.  We  would  be  glad  to  see  Roper's  hand-books 
largely  multiplied  and  distributed  in  every  workshop,  for  it  is  only  out  of  books 
of  this  kind  that  the  average  workman  will  be  able  to  master  the  principles  of 
his  handiwork.  The  present  volume  is  no  exception  to  this  rule;  on  the  con- 
trary, we  regard  it  to  be  decidedly  the  best  of  Mr.  Roper's  books,  Jboth  with 
regard  to  its  substance  and  the  manner  in  which  the  same  is  classified  and  pre- 
sented. 

The  Locomotive,  Hartford,  Conn. 

Roper's  Engineer's  Handy-Book.— Published  by  E.  Claxton  &  Co.,  of 
Philadelphia,  who  are  the  publishers  of  several  works  on  steam,  steam-boilers,  and 
engines,  from  Mr.  Roper's  pen.  This  last  work  is  of  special  value  to  all  who 
have  to  do  with  steam-boilers  and  engines,  and  it  will  be  found  a  valuable  shop 
companion  for  the  mechanic.  There  are  a  great  many  facts  collated  that  are 
not  easily  reached  except  through  expensive  books  and  libraries.  These  will  be 
found  of  service  to  all  classes  of  men,  whether  in  trade  or  manufacturing.  We 
commend  it  heartily,  and  believe  it  will  have  a  large  sale. 

National  Car-Builder,  Neiv  York. 

Roper's  Engineer's  Handy-Book.— This  compact  and  comprehensive  little 
volume  contains  a  vast  amount  of  information  relative  to  the  care  and  manage- 
ment of  every  class  of  steam-engines.  It  is  profusely  illustrated,  and  abounds 
in  facts,  figures,  rules,  tables,  questions  and  answers,  formulie,  etc.,  that  are  ex- 
ceedingly valuable  to  engineers,  and  of  easy  reference  by  means  of  a  copious 
and  well-arranged  index.    The  various  subjects  are  discussed  with  brevity  and 

1 


OPINIONS   OF   THE  PRESS. 


clearness,  and  with  a  freedom  from  technicality  which  enables  the  reader  to  get 
at  the  pith  of  the  matter  without  fishing  it  out  from  an  ocean  of  words.  A  prom- 
inent feature  of  the  book  is  a  full  explanation  of  the  steam-engine  indicator,  and 
its  use  and  advantages  to  engineers  and  others.  The  long  experience  of  the 
author  in  this  branch  of  engineering,  and  the  numerous  publications  he  has  al- 
ready issued  upon  kindred  subjects,  give  an  additional  value  to  the  present 
treatise.  It  is  printed  on  thin  paper  and  in  clear  type,  and  contains  678  pages. 
Flexible  tuck  binding,  gilt  edge,  suitable  for  the  pocket. 

Forest^  Forge^  and  Farm,  Ilion,  New  York. 

Engineer's  Handy-Book.—  We  have  received  a  book  with  the  above  title, 
by  the  well-known  author  and  engineer,  Stephen  Roper,  who  has  written  a 
number  of  works  on  the  subject  of  engineering.    The  eminent  reputation  of  the  i 
author  is  a  sufiicient  guarantee  that  the  book  is  both  interesting  and  useful.  *! 
Mr.  Roper  has  had  an  experience  of  over  thirty-five  years  with  all  kinds  of  en- 
gines and  boilers,  and  thoroughly  understands  locomotive,  fire,  marine,  and 
stationary  engines.    This  work  has  678  pages,  is  profusely  illustrated,  bound  in  1 
morocco,  and  contains  nearly  300  main  subjects,  1316  paragraphs,  876  questions 
and  answers,  52  suggestions  and  instructions,  105  rules,  formulae,  and  examples, 
149  tables,  195  illustrations,  31  indicator  diagrams,  and  167  technical  terms ; 
over  3000  different  subjects,  with  the  questions  most  likely  to  be  asked  when  j 
under  examination,  before  being  commissioned  as  an  engineer  in  the  U.  S.  Navy  i 
or  revenue  service ;  before  being  licensed  as  an  engineer  in  the  mercantile  marine 
service,  or  receiving  a  certificate  to  take  charge  of  a  steam-engine  or  boiler  in 
locations  where  such  certificate  is  necessary. 

It  is  a  very  valuable  book  for  engineers,  and  will  no  doubt  meet  with  a  read;^ 
sale.   E.  Claxton  &  Co.,  Philadelphia,  are  the  publishers. 

LeffeVs  Illustrated  News,  Springfield ,  Ohio. 

Engineer's  Handy-Book  :  By  Stephen  Roper,  Engineer.—  The  author  of 
the  valuable  series  of  hand-books  which  we  have  before  referred  to,  has  just 
issued  the  above-named  work,  which  must  find  ready  way  into  the  hands  of  en- 
gineers and  steam-users  throughout  the  entire  land.  It  contains  a  full  explana- 
tion of  the  steam-engine  indicator,  its  uses  and  advantages,  with  formulae  for 
estimating  the  power  of  all  classes  of  steam-engines ;  also  facts,  figures,  questions 
and  tables  for  engineers  who  wish  to  qualify  themselves  for  the  United  States 
navy,  the  revenue  service,  the  merchant  marine,  or  the  better  class  of  stationary 
engines.  The  work  does  not  claim  to  teach  how  to  design  or  proportion  steam- 
engines  and  boilers,  but  rather  to  inform  the  engineer  how  to  manage  them 
intelligently.  It  is  one  of  the  kind  of  practical  hand-books  for  which  there  is 
always  neeJ.  The  work  is  well  bound  in  flexible  leather,  uniform  with  Roper's 
other  hand-books,  has  678  pages,  and  is  fully  illustrated. 

2 


OPINIONS    OF    THE  PRESS. 


American  Machinist ,  New  York, 

Roper's  Engineer's  Handy-Book. —  The  subjects  in  this  work  have  neen 
treated  in  a  brief  and  comprehensive  way,  therefore  the  reader  is  not  required 
to  read  a  number  of  chapters  in  order  to  acquire  a  little  knowledge.  The  use 
of  the  indicator  is  treated  in  a  plain,  practical  way,  so  that  it  may  be  readily 
understood.  Abstruse  formulas  have  been  omitted  and  simple  arithmetic  used, 
thus  avoiding  the  usual  vexations  among  practical  men,  who  are  uneducated  in 
the  higher  mathematics.  The  author  has  in  this  book  given  the  results  of  his 
own  practical  experience,  which  extends  over  a  period  of  thirty  years  and  up- 
wards, and  the  work  will  doubtless  be  read  with  pleasure  and  profit  by  very 
many  practical  mechanics. 

Boston  Journahof  Commerce, 

Mr.  Stephen  Roper  is  well  known  as  the  author  of  several  other  handy-books 
that  treat  on  steam,  steam-boilers,  and  engines.  This  new  work  is,  in  our  judg- 
ment, his  best.  Although  the  arrangement  and  classification  seem  a  little 
peculiar,  and  a  decided  new  departure  in  book-malting,  they  do  not  detract  from 
the  merit  of  the  book,  which  is  plain,  comprehensive,  and  instructive  from  the 
title-page  to  The  End."  It  is  neatly  illustrated,  and  creditable  in  the  highest 
degree  to  both  author  and  publishers.  It  will  be  a  valuable  addition  to  every 
engineer's  library. 

Millstone^  Indianapolis ,  Ind, 

The  Engineer's  Handy-Book,"  by  Stephen  Roper,  Engineer,  is  a  practi- 
cal treatise  on  the  management  of  the  steam-engine.  The  author  says  the  book 
was  not  written  for  the  purpose  of  instructing  engineers  how  to  design  or  pro- 
portion steam-engines  or  boilers,  but  rather  to  inform  them  how  to  take  care  of 
and  manage  them  intelligently."  The  declaration  is  carried  out  in  the  plainest 
and  most  systematic  manner.  There  is  no  straining  after  possibilities,  but  the 
facts,  as  a  thorough  mechanic  and  engineer  understands  them,  are  set  forth  in 
positive  language  and  plain  terms.  This  gives  value  to  the  work  as  a  hand-book 
to  such  engineers  who  are  not  too  egotistical  to  receive  information.  As  a  text- 
book for  students  in  mechanical  engineering,  it  will  be  found  of  great  value.  Its 
illustrations  and  tabulated  matter  are  important  features,  and  printed  in  the  ex- 
cellent style  that  characterizes  all  the  books  issued  from  the  house  of  E.  Claxton 
&  Co.,  Philadelphia.  It  is  something  that  should  be  possessed  by  every  engi- 
neer. 

TJie  Ainerican  Engineer*,  Cli  icago,  111. 

The  Engineer's  Handy-Book.— We  are  in  receipt  of  the  above  work, which 
contains  a  description  of  the  various  forms  of  engines  now  in  use,  and  supplies 
interesting  and  useful  information  as  to  the  care,  management,  and  remedy  of 

3 


OPINIONS   OF   THE  PRESS, 


defects  of  steam  machinery  and  its  appendages,  with  tables  for  calculating  the 
power  of  engines.  Mr.  Roper  in  his  preface  says :  "  This  book  was  not  written 
for  the  purpose  of  instructing  engineers  how  to  design  or  proportion  steam-en- 
gines or  boilers,  but  rather  to  inform  them  how  to  take  care  of  and  manage 
them  intelligsntly,  as  well  as  to  furnish  to  those  intending  to  qualify  themselves 
for  the  United  States  Navy,  Revenue  Service,  Mercantile  Marine,  or  to  take 
charge  of  the  better  class  of  stationary  steam-engines,  with  a  plain,  practical 
treatise."  It  is  from  this  standpoint,  therefore,  that  the  book  ought  to  be  judged, 
and  we  are  sure  that  the  large  class  to  whom  it  is  especially  addressed  will  find 
it  a  useful  appendage  and  book  of  reference  in  their  daily  work. 

The  Scientific  American^  Kew  Yorh. 

A  well-made  pocket-book  of  practical  information  for  mechanical  engineers, 
particularly  those  of  limited  education,  and  such  as  may  wish  to  qualify  them- 
selves for  service  in  the  U.  S.  Navy  or  the  mercantile  marine.  The  more 
important  engines  in  use  are  clearly  described,  and  formulae  are  given  for 
estimating  their  power.  Pai^ticular  attention  is  paid  to  the  Steam-Engine  In- 
dicator, its  use  and  advantages.  The  author  has  hpd  much  experience  in  this 
class  of  work,  and  writes  clearly  and  plainly. 

Engineering  News^  New  YorJc. 

An  "  Engineer's  Handy-Book."— As  a  writer  on  subjects  relating  to  steam 
and  steam  engineering,  Mr.  Roper  is  now  too  well  known  to  need  any  further 
introduction.  In  this,  his  latest  contribution  to  steam-engineering  literature, 
Mr.  Roper  has  aimed  to  present  to  his  brother  engineers  a  "  handy-book"  that 
will  be  to  them  what  Trautwine*s  "  Pocket-Book"  is  to  civil  engineers,  and  in 
doing  this  he  has  spared  no  labor  in  collecting  and  editing  his  materials.  Some 
idea  of  the  completeness  of  the  work  may  be  gathered  from  the  statement  of 
the  publishers  that  it  contains  nearly  300  main  subjects,  1316  paragraphs,  876 
questions  and  answers,  52  suggestions  and  instructions,  105  rules,  formulae,  and 
examples,  149  tables,  164  illustrations,  31  indicator  diagrams,  and  167  technical 
terms ;  over  3,000  ditferent  subjects,  with  the  questions  most  likely  to  be  asked 
when  under  examination,  before  being  commissioned  as  an  engineer  in  the  U.  S. 
Navy  or  Revenue  Service ;  before  being  licensed  as  an  engineer  in  the  Mercantile 
Marine  Service,  or  receiving  a  certificate  to  take  charge  of  a  steam-engine  or 
boiler  in  locations  where  such  certificate  is  necessary.  The  author  does  not 
claim  to  have  discovered  any  recent  special  facts  relating  to  his  subject,  neither 
does  he  claim  to  have  written  a  book  of  instructions  in  designing  or  proportion- 
ing steam-engines ;  he  aims  rather  to  instruct  how  to  care  for  and  manage  them 
intelligently.  The  book  is  very  full  and  complete,  and  its  typographical  execu 
tion  is  perfect.  It  must  readily  recommend  itself  as  an  "ever-ready  com.* 
panion  "  to  every  steam-ei^gineer  in  the  country. 

4 


OPINIONS  OF  THE  PRESS. 


From  the  Textile  Colorist,  Philadelphia, 
The  Engineer's  Handy-Book. — Another  aid  to  engineering  by  a  well 
known  author,  who  has  already  done  much  in  the  way  of  practically  educa- 
ting scientific  students.  The  work  before  us  is  one  of  678  pages  of  the  mpst 
useful  information.  It  treats  exhaustively  on  the  most  recently  invented  ad- 
juncts to  the  steam-engine,  and  gives  very  full  formula  by  which  engineers  can 
accurately  calculate  power  and  make  reliable  estimates  in  all  branches  of  theii 
profession.  It  likewise  presents  the  most  desirable  instructions  to  y«  nng  meu 
wishing  to  stand  examination  for  the  United  States  Navy  or  Revenue  {service,  m 
well  as  the  merchant  marine.  It  is  fully  illustrated,  and  got  up  in  a  stvle  com 
mendable  in  the  publishers  and  flattering  to  the  author. 

From  the  American  Manufacturer  and  Iron  WorM^ 
Fittshurg^  Fa. 

The  Engineer's  Handy-Book  :  By  Stephen  Roper,  Engineer.— iir.  Rope)  p 
name  is  by  no  means  unfamiliar  to  the  readers  of  popular  8team-eng:neeri)ig 
literature  in  this  country.  The  book  now  under  notice  is  his  last,  and  we  )>e- 
lieve  the  largest  in  bulk  and  the  most  comprehensive  in  scope  of  any  work  vet 
published  by  him.  He  has  gathered  into  this  single  volume  about  ah  die  piac- 
tical  information  relating  to  the  care  and  management  of  a  steam-eugine  thai 
one  eni ployed  as  a  steam-engineer  would  be  likely  to  require  in  ordinary  service. 
The  leading  steam-engines  now  in  the  market  are  illustrated  in  th)s  book  with 
more  or  less  descriptive  matter  accompanying  each,  giving  the  reader  a  general 
Idea  of  the  design  of  the  engines,  the  details  of  their  construction  and  operation. 
The  various  accessories  to  engines  and  boilers  receive  their  full  share  of  atten- 
tion. The  chapter  relating  to  the  indicator  is  well  illustrated  by  means  of  nu- 
merous and  well  chosen  diagrams. 

The  paper,  press-work,  and  the  general  make  up  of  the  book  leave  nothing  to 
be  desired.  The  style  in  which  the  book  is  written  will  commend  itself  to  those 
who  want  a  book  to  read,  and,  thererore,  free  from  mathematical  formuiae  and 
we  have  no  doubt  that  the  class  of  persons  whom  Mr.  Roper  addresses  will  find 
in  this  book  all  they  will  be  likely  to  want  in  connection  witb  any  quejitiou  re- 
lating to  the  steam-engine. 

6 


OPINIONS   OF   EMINENT   ENGINEERS,  ETC. 


The  following  letters  have  been  received  from  some 
of  the  most  distinguished  mechanical  engineers,  ex- 
perts, and  authors  in  the  country. 

E,  Claxton  &  Co,  ancmnati,  Ohio,  Aug.  5,  1880. 

Permit  me  to  acknowledge  copy  of  your  Eoper'^s  Engineer's  Handy- 
Book,  The  volume  contains  a  large  amount  of  useful  information  for 
students  of  mechanical  engineering^  arranged  in  a  condensed  form.,  and 
cannot  fail  to  he  a  valuable  acquisition  to  young  engineers  and  me- 
chanics,  JOHN  W,  HILL. 


E,  Claxton  &  Co,  Yonkers,  N.  Y.,  Aug.  Ik,  1880. 

In  rejjly  to  your  favor  of  the  2d  instant.,  Iwoidd  say  that  I  think  Mr. 
Eoper'^s  Engineer'' s  Handy-Book  "  is  the  best  one  of  his  recent  works. 
Permit  me  to  say  that,  when  asked,  as  I  of  ten  am,  by  the  men  I  meet  in 
charge  of  engines,  as  to  what  books  they  had  best  get  ''to  read  up  on  the 
engine,''''  I  say  ''get  Boper''s  Works,'''  In  the  fidure,  as  in  the  past, 
I  shall  take  pleasure  in  endorsing  his  effort  to  the  men  for  whom  he  has 
written,  W.  H,  ODELL, 


Messrs,  E,  Claxton  dc  Co.  Troy,  N.  f.,  Aug.  ii,  mo. 

Your  favor  of  a  late  date,  as  well  as  enclosure  of  "Boper''s  Engi- 
neer's Handy -Book,''''  duly  received.  Permit  me  to  say,  that  I  think 
th-e  book  a  very  valuable  addition  to  the  literature  of  the  subjects  of 
which  it  treats;  and,  while  the  accomplished  engineer  will  fiiid  in  this 
book  many  facts  so  pAainly  stated  as  to  save  much  time  in  icorking  up, 
the  intelligent  engineer  and  mechanic,  whose  opportunities  in  the  past 
have  hardly  permitted  his  becoming  fitted,  and  whose  time  in  the  present 
will  hardly  allow  him  to  wade  through  the  verbiage  and  mathematical 
demonstrations  in  tohich  such  knowledge  as  is  contained  in  Mr,  Boper''s 
book  is  usually  enveloped,  ivill  find  in  it  a  large  amount  of  information 
stated  in  the  common  language  of  every -day  life.  Such  books  cannot  be 
too  widely  distributed.  The  time  was  when  their  possession  was  a  con- 
venience, TJie  time  is  ichen  their  possession  is  almost,  if  not  quite,  a 
necessity.  F,  F,  HEMENWAY, 

Claxton  &  Co,    -  Passaic,  N.  J,  Aug.  U,  1880. 

I  have  examined  " Roper ''s  Handy-Book pretty  thoroughly,  and 
have  no  hesitancy  in  pronouncing  the  loork  an  excellent  one.  It  is  de- 
cidedly out  of  the  beaten  track,  and  the  better  for  it, 

WM,  H.  HOFFMAN. 


OPINIONS   OF   EMINENT   ENGINEERS,  ETC. 


E,  Claxton  &  Co.  aucago,  m.,  Aug.  18,  1880. 

Your  note  of  July  S9th,  and  a  copy  of  ^^Boper's  Engineer's  Handy- 
Book,''''  were  duly  received.  The  book  is  well  calculated  to  accomplish 
the  purpose  of  the  author,  viz,,  to  furnish  practical  and  valuable  infor- 
mation to  engineers.  The  comprehensive  description  of  the  various 
types  of  automatic  engines  is  a  fund  of  useful  knowledge,  and  the  various 
groups  of  questions,  the  answers  to  which  are  embodied  in  the  text,  are 
very  likely  to  cause  readers  to  "  think,''^  and  to  fasten  the  ideas  in  their 
minds.    The  book  is  a  desirable  addition  to  an  engineer'' s  library, 

CHARLES  A,  HAGUE, 

E,  Claxton  &  Co,  Hamilton,  Ohio,  Aug.  30,  1880. 

Your  esteemed  favor ,  and  also  a  copy  of  Boper'^s  Engineer'' s  Handy- 
Book,  were  duly  received;  and,  in  reply,  I  beg  leave  to  say  that  the  work 
is  well  got  up,  and  I  consider  it  of  more  practical  value  than  any  Ihave 
yet  seen.  It  seems  almost  impossible  to  find  steam  literature  adapted  to 
the  tvants  of  steam  users.  This  book  fulfils  this  requirement,  and  de- 
serves a  good  reception  at  the  hands  of  a  class  of  men  whom  it  may 
greatly  benefit.  J,  W,  SEE,  * 

E,  Claxton  &  Co,  Hartford,  Conn.,  Sept.  8,  1880. 

Your  favor  of  the  29th  of  July  came  in  my  absence,  I  have  just 
returned,  and  hasten  to  reply,  Boper''s  Engineer'' s  Handy-Book  is  re- 
plete with  the  information  that  Engineers  need  at  hand.  It  combines 
such  portions  of  more  pretentious  works  not  readily  accessible  to  the 
Engineer,  as  well  as  information  from  Mr,  Boper''s  wide  practical 
experience  with  the  detailed  icorking  of  Boilers  and  Engines,  as  icill 
give  it  value  in  the  Shop  and  Engine-room,  But  it  has  a  wider  range 
than  this.  It  contains  valuable  tables,  articles  on  the  U.  S,  Naval  Ser- 
vice, Bevenue  Service,  and  Mercantile  Service,  icith  qualifications  re- 
quired of  persons  seeking  appointments  in  each,  and  numerous  other 
matters  that  make  the  work  a  very  valuable  compendium.  I  shall  keep 
a  copy  on  my  desk  ready  for  reference,  and  cheerf  ully  commend  it  to 
others.  Business  men  and  manufacturers  will  find  it  a  very  convenient 
Hand-Book,  J,  M.  ALLEX, 

President  Hartford  Steam-Boiler  Inspection  and  Insurance  Company. 


OPINIONS    OF    EMINENT    ENGINEERS,  ETC. 


E.  ClaxtOn  &  Co,  aiumbut,  Ohio,  Oct.  tS,  1890. 

I  esteem  this  book  highly  as  one  containing  much  information  not 
found  elsewhere  in  a  condensed  form.  It  hears  directly  on  practical 
questions  in  mechanical  engineering,  especially  on  matters  pertaining 
to  the  Indicator  and  its  use.  How  to  read  a  diagram  and  determine 
the  condition  of  the  action  of  engines  are  made  clear. 

The  hooJc  is  of  especial  value  to  any  who  may  be  interested  in  the 
peculiarities  of  existing  engines,  as  I  find  the  book  contains  illustrations 
and  descriptions  of  most  of  the  prominent  engines  in  use, 

S,W.  EOBINSON, 

Prqf.  <if  Mechanical  Engineering,  Ohio  State  University. 
E.  UlaXtOn  &  Co.  ^^^on,  Nov.  tU,  1880. 

I  can  give  my  opinion  of  Roper'' s  Engineer's  Handy-Book  in  a  few 
words :  it  is  the  book  that  has  been  needed  for  more  than  50  years.  It 
is  the  only  book  on  steam  and  the  steam-engine  that  I  know  of  which 
is  devoid  of  the  mysteries  of  algebraical  formulae,  and  which  the  engi- 
neer or  student,  with  only  a  common-school  education,  can  read  and 
understand;  it  consequently  leaver  no  excuse  for  the  ordinary  engineer 
to  be  ignorant  of  the  principles  of  steam-engines. 

F,W,  BACON,  M.E. 

E.  Claxton  &  Co.  mbohen,  N.  J.,  Dec.  51, 1880, 

Gentlemen : — I  am  in  receipt  of  your  favor  arid  also  a  copy  of  Boper's 
Engineer's  Handy-Book;  please  accept  thanks  for  the  same,  lam  too 
much  occupied  with  collegerwork  at  the  present  time  to  give  it  a  complete 
analysis,  but  at  a  cursory  gl/xnce  I  see  it  is  full  of  valuable  information 
for  those  who  use  or  handle  steam-engines,  and  should  think  it  would 
have  a  very  extensive  sale. 

R.  H.  THURSTON. 

Prqf.  oj  Jltchani^al  ScU.nce^  Slevem  Institute  q/  Technology t 


ENGINEER'S  Handy-Book. 

CONTAINING 

A  FULL  EXPLANATION  OF  THE  STEAM-ENGINE 
INDICATOR,  AND  ITS  USE  AND  ADVANTAGES 
TO  ENGINEERS  AND  STEAM  USERS. 

WITH  FORMULA 

FOR  ESTIMATING  THE  POWER  OF  ALL  CLASSES  OF  STEAM-ENGINES; 
ALSO,  FACTS,  FIGURES,  QUESTIONS,  AND  TABLES  FOR  ENGINEERS 
WHO  WISH  TO  QUALIFY  THEMSELVES   FOR   THE  UNITED 
STATES  NAVY,  THE   REVENUE    SERVICE,  THE  MER- 
CANTILE MARINE,  OR  TO  TAKE  CHARGE  OF 
THE  BETTER  CLASS  OF  STATIONARY 
STEAM-ENGINES. 

BY 

STEPHEN  ROPER,  Engineer, 

Author  of 

"'Roper's  Catechism  of  Hign-Pressure  or  Is  on-Condensing  Steam-Enginee," 
"Roper's  Hand-Book  of  the  Locomotive,"  "Roper's  Hand-Book  of 
Land  and  Marine  Engines,"  "Roper's  Hand-Book  of  Modern 
Steam-Fire  Engines,"  "Improvements  in  Steam-Engines," 
"Use  and  Abuse  of  the  yieaui-Boiler,"  "  Queatioiia  ana 
Answers  for  Engineers,"  etc.,  etc. 


THIRTEENTH  EDITION. 


PHILADELPPIIA: 
EDWARD  MEEKS, 
1012  Walnut  Street. 
1892. 


Copyright. 
CLAXTON  &  CO. 
1881 


INTRODUCTION. 


r 


T  is  quite  customary  for  persons  to  write  bobks  on  the  steam-en. 
gine,  and  then  offer  as  an  apology  for  so  doing,  that  they  have 
discovered  that  there  is  no  practical  treatise  on  the  same  subject  in 
the  market,  which  shows  either  a  lack  of  modesty  on  their  part,  and 
a  want  of  appreciation  of  what  has  already  been  written,  or  an  un- 
willingness to  do  justice  to  those  who  have  previously  treated  the 
same  subject.    There  is  no  want  of  literature  on  the  steam-engine ; 
in  fact,  it  would  be  difficult  for  the  most  experienced  engineer  or 
talented  author  to  add  anything  original.  The  steam-engine  of  the 
present  day  is  probably  as  perfect  as  it  ever  will  be ;  in  fact,  there 
has  not  been  any  important  improvement  made  in  any  class  of 
steam-engines  for  several  years,  except  in  the  quality  of  the  mate- 
rials employed  in  their  construction  and  refinement  of  workman, 
ship;  consequently,  the  work  of  those  wiio  treat  on  the  steam- 
engine,  for  the  present,  must  be  confined  simply  to  abbreviating, 
simplifying,  correcting,  and  explaining  what  has  already  been  Nvrit- 
ten,  as  well  as  noting  the  results  of  the  experiments  which  are  tried 
to  test  the  efiiciency  of  different  designs  of  steam-engines.  AVho- 
ever  will  apply  himself  to  this  object  in  the  future,  will  be  per- 
^  forming  what  has  long  been  needed.    Of  course,  we  may  discover 
<^  a  new  engine  that  will  be  radically  different  from  any  in  use  at  the 
^  p^sent  day,  which  would  involve  the  necessity  of  a  new  order  of 
^  literature  and  new  theories,  but  such  an  innovation  is  highly  im- 
probable, and  casts  only  a  dim  shadow  in  the  future, 
^^his  book  was  not  w^ritten  for  the  purpose  of  instructing  engi- 
I     neers  how  to  design  or  proportion  steam-engines  or  boilers,  but  rather 
to  inform  them  how  to  take  care  of  and  manage  them  intelligently. 


X 


INTRODUCTION. 


as  well  as  to  furnish  to  those  intending  to  qualify  themselves  for  the 
United  States  Navy,  Revenue  Service,  Mercantile  Marine,  or  to 
take  charge  of  the  better  class  of  stationary  steam-engines,  with  a 
plain,  practical  treatise.  In  order  to  enhance  its  value  to  young 
engineers,  as  well  as  those  of  limited  education,  none  but  the  plainest 
language  has  been  used.  This  has  not  been  done  for  the  purpose  of 
encouraging  the  engineer  to  dispense  with  the  use  of  mathematics, 
or  discard  theories,  sis  all  our  great  triumphs  in  mechanical  science 
have  been  based  on  theories  and  demonstrated  by  practice. 

In  the  discussion  of  the  different  subjects  brevity  has  been  ad- 
hered to,  because  the  spirit  of  the  age  demands  it,  even  in  the  dis- 
cussion of  the  most  important  subjects.  There  can  be  no  reason 
why  the  reader  should  be  compelled  to  wade  through  chapters  of 
matter  to  obtain  information  which  may  be  condensed  into  a  few 
terse  and  intelligent  paragraphs,  nor  to  deal  with  the  dead  past 
when  the  living  present  is  before  him.  The  mathematical  formulae 
employed  have  been  abbreviated,  since  it  is  immaterial  how  a  prob- 
lem is  worked,  providing  the  result  is  correct  and  susceptible  of 
easy  explanation.  Up  to  the  present  time,  the  knowledge  to  intelli- 
gently apply  the  steam-engine  indicator  has  been  confined  to  a  few 
persons  in  every  country  styling  themselves  experts.  This  partly 
arose  from  the  fact  that  authors  who  have  heretofore  treated  on 
this  subject  were  men  of  literary  ability  and  well  versed  in  mathe- 
matics, who  found  it  more  agreeable  to  elucidate  their  subject  in 
their  own  peculiar  style  than  in  any  other. 

The  writer's  experience  of  over  thirty-five  years,  and  his  asso- 
ciation with  all  classes  of  engineers,  enable  him  to  understand  fully 
the  kind  of  information  most  needed  by  the  average  engineer.  Con- 
sequently, he  has  undertaken  the  task  of  furnishing  it,  and  how  we^l 
he  .has  succeeded  in  the  accomplishment  of  his  object,  he  cheerfully 
leaves  to  the  reader  to  decide.  If  it  should  appear  that  he  has  suc- 
ceeded in  imparting  useful  and  important  information  to  the  mem- 
bers of  a  profession  to  which  he  himself  belongs,  he  will  feel  amply 
rewarded  for  his  efforts.  S.  E. 


CONTENTS. 


JPor  a  full  reference  to  the  Contents  in  detail,  see  Index,  p,  673. 


PART  FIRST. 

PAGE 

The  Centennial  Corliss  Engines   25 

Steam  Engineering  .27 

Facts  that  should  be  Borne  in  Mind  by  Engineers      .      .  34 

Wright's  Automatic  Cut-Off  Engine   38 

Examination  of  Candidates   40 

Necessary  Qualifications  of  Candidates  Applying  for  Ap- 
pointments AS  Cadet  Engineers  in  the  U.  S.  Navy   .      .  40 

Examination  in  Grammar   42 

Spelling   43 

Examination  in  Arithmetic   43 

Examination  in  Geography   47 

Examination  in  Natural  Philosophy   49 

Woodbury,  Booth  &  Pryor  Automatic  Cut-Off  Engine  .      .  52 

Qualifications  of  Candidates  for  the  U.  S.  Revenue  Service  57 
Standard  of  Examination  for  Assistant  Engineer  in  the  U.  S. 

Revenue-Cutter  Service                                                .  58 

First  Assistant  Engineer   58 

Examinations  for  the  Mercantile  Marine  Service       .      .  59 

Qualifications  of  Stationary  Engineers   60 

Locomotive  Engineers     .      .      .  .      .      .      .  .62 

Steam   63 

Table  showing  the  Increase  of  Sensible  and  the  Decrease  of  Latent 

Heat  in  Steam,  according  to  Pressure   65 

Table  showing  the  Effluent  Velocity  with  which  Steam,  at  difierent 
Pressures,  will  Flow  into  the  Atmosphere,  or  into  Steam  at  a  lower 

Pressure   67 

xi 


xii 


CONTENTS. 


PAGE 


EuLE  FOR  Finding  the  Amount  of  Gain  derived  from  Work- 
ing Stea^  Expansively  67 

Table  of  Hyperbolic  Logarithms  to  be  used  in  Connection  with  the 
above  Eule  68 

Table  of  Multipliers  by  which  to  find  the  Mean  Pressure  of  Steam  at 
Various  Points  of  Cut-Off  69 

Table  of  Constant  Numbers  by  which  to  Ascertain  the  Average  Press- 
ure of  the  Steam  against  the  Piston  for  different  Pressures  and  Points 
of  Cut-Off,  from  ^  to  |  of  the  Stroke  69 

Table  of  Constant  Numbers  for  Finding  the  required  "Lap"  for  Slide- 
Yalves  when  the  Travel  of  the  Valve  is  known      .       .       .  .70 

Table  showing  the  Average  Pressure  of  Steam  upon  the  Piston  through- 
out the  Stroke,  when  Cut-Off  in  the  Cylinder  is  from  J  to  |,  com- 
mencing with  10  Pounds  and  advancing  in  5  Pounds  up  to  55 
Pounds  Pressure  71 

Table  showing  the  Average  Pressure  of  Steam  upon  the  Piston 
throughout  the  Stroke,  when  Cut-Off  in  the  Cylinder  is  from  J  to  |-, 
commencing  with  60  Pounds  and  advancing  in  5  Pounds  up  to  105 
Pounds  Pressure  72 

Table  showing  the  Average  Pressure  of  Steam  upon  the  Piston 
throughout  the  Stroke,  when  Cut-Off  in  the  Cylinder  is  from  J  to  J, 
commencing  with  110  Pounds  and  advancing  in  5  Pounds  up  to 
150  Pounds  Pressure  73 

Table  showing  the  Temperature  of  Steam  at  different  Pressures,  from 
1  Pound  per  Square  Inch  to  220  Pounds,  and  the  Quantity  of  Steam 
produced  from  a  Cubic  Inch  of  Water,  according  to  Pressure  .  .74 
Explanation  of  Table  76 

Table  of  Elastic  Force,  Temperature,  and  Volume  of  Steam  from  a 
Temperature  of  32°  to  457°  Fah.,  and  from  a  Pressure  of  0*2  to  900 
Inches  of  Mercury  76 


Table  showing  the  Temperature  and  Weight  of  Steam  at  different  Press- 
ures from  1  Pound  per  Square  Inch  to  300  Pounds,  and  the  Quantity 
of  Steam  produced  from  1  Cubic  Foot  of  Water,  according  to  Pressure  81 

Table  showing  the  Steam  Pressure  in  Pounds  per  Gauge ;  the  Abso- 
lute Pressure  in  Pounds  and  Inches  of  Mercury  ;  the  Temperature  ; 
the  Total  Heat  in  Steam  per  Pound ;  the  Latent  Heat  per  Pound ; 
the  Heat  of  the  Water;  the  Eelative  Volume  and  Weight  of  Steam 


per  Cubic  Foot  for  various  Pressures       .       .       .       .       .  .85 

The  Brown  Automatic  Cut-Off  Steam-Engine  .      .      .  .88 

The  Harris  Corliss  Steam-Engine  95 

Questions  for  Engineers  99 


CONTENTS. 


Xlll 


PART  SECOND. 

PAGE 

Hteam-Engines  in  Generate  102 

Compound  Engines  109 

Simple  Engines  112 

Table  of  the  Average  Performances  of  different  Designs  of  Pum ping- 
Engines   114 

Uncertainty  of  Tests  for  the  Purpose  of  Comparing  the 

Kelative  Economy  of  Marine  Engines  116 

The  Locomotive  119 

The  Steain^  Fire-Engine  120 

The  Woodruff  and  Beach  Automatic  Cut-Off  High-Pressure 

Engine  124 

Automatic  Cut-Off  and  Throttling  Engines     ....  130 

Throttling  Engines  131 

Steam-Engine  Cut-Offs     .      .      .  132 

Design  of  Steam-Engines  134 

Duplicating  the  Parts  of  Steam-Engines  136 

Fitting  the  Cranks  of  Steam-Engines  to  their  Shafts  .  137 
The  Putnam  Machine  Company's  Automatic  Cut-Off  Engine  138 

How  TO  Put  an  Engine  in  Line  141 

How  TO  Set  up  a  Stationary  Engine  ......  143 

How  TO  Keverse  an  Engine  145 

How  TO  Eepair  Steam-Engines  146 

How  TO  Increase  the  Power  of  the  Steam-Engine  .  .  .148 
The  Greene  Automatic  Cut-Off  High-Pressure  Engine  .      .  150 

The  Dead-Centre  152 

The  Causes  of  Knocking  in  Steam-Engines  ....  153 
The  Kemedies  for  Knocking  in  Steam-Engines  ....  155 

The  Douglas  Automatic  Cut-Off  Engine  159 

Technical  Terms  Applied  to  Different  Parts  of  Steam-Engines  160 
Terms  Formerly  Applied  to  Different  Parts  of  Steam-En- 
gines, but  which  have  become  Obsolete      ....  161 
Questions  162 

PART  THIRD. 

Bed-Plates  and  Housings  163 

Steam-Cylinders  .   164 

Table  showing  the  Proper  Thickness  for  Steam-Cylinders  from  6  to  90 

Inches  166 

2 


xiv 


CONTENTS. 


PAGE 


Steam-Pistons  167 

piston-kods  169 

Table  of  Units  of  Horse-Power  for  different  Piston  Speeds       .       .  170 
Table  showing  Length  of  Stroke  and  Number  of  Revolutions  for  dif- 
ferent Piston  Speeds  in  Feet  per  Minute  172 

Piston,  Connecting-Rod,  and  Crank  Connections       .      .      .  175 

The  Reynolds  Corliss  Engine  177 

Steam-  and  Exhaust-Pipes  180 

Rock -Shafts  .181 

Cross-Head  Bearings.      .  181 

Valve-Rods  182 

The  Eccentric   .182 

The  Crank  183 

Crank-Pins  185 

Crank-Shaft  Journals  and  Main-Bearings       ....  187 

Keys,  Gibs,  and  Straps  188 

The  Link     ....   189 

Fly- Wheels  192 

The  Watertown  Automatic  Cut-Off  Engine     ....  194 

Steam-Engine  Governors  .      .      .  -  197 

How  TO  Balance  the  Reciprocating  and  Revolving  Parts 

OF  Vertical  Engines   .      .  202 

Heating  in  Journals  and  Reciprocating  Parts  of  Steam- 

Engines   202 

Reversing-Gear  for  Marine  Engines  203 

The  Slide- Valve  205 

The  Wheelock  Automatic  Cut-Off  Engine       ....  214 
How  TO  Determine  the  Amount  of  Lap  and  Lead  on  a  Valve 
WITHOUT  Opening  the  Steam-Chest,  and  whether  it  is 

Equal  at  both  Ends  or  not  218 

Table  showing  the  Amount  of  "  Lap"  required  for  Slide- Valves  when 

the  Steam  is  to  be  Worked  expansively  220 

Friction  of  Slide- Valves  221 

How  TO  Set  the  Valves  of  Steam-Engines  224 

Valves  and  Valve-Gear   .      .      .  226 

Valves  and  Cocks  connected  with  Engines  and  Boilers      .  229 

Pipes     .  231 

The  Wells  Two-Piston  Balance-Engine  232 

Instructions  for  the  Care  of  Steam-Engines    ....  235 

PiSTON-RoD  AND  VaLVE-RoD  PACKING,  AND  HoW  TO  USE  IT  .  237 

Wardwell's  High-Pressure  Valveless  Engine  ....  240 


CONTENTS, 


XT 


PAGE 


Lubricants  248 

Questions  246 

PART  FOURTH. 

The  Steam-Engine  Indicator  :  Its  Invention  and  Improvement  251 

Tabor's  Indicator  259 

Functions  of  the  Indicator  261 

Technical  Terms  Used  in  Connection  with  the  Employment 

OF  the  Indicator   263 

How  TO  Attach  the  Indicator  268 

Motion  of  the  Paper  Drum  269 

The  Most  Accurate  Methods  of  Testing  the  Adjustments  .  274 
Diagrams  taken  from  Automatic  Cut-Off  Engines  .       .      ,  278 

Application  of  the  Theoretic  Curve  280 

The  Initial  Pressure,  or  Steam-Line  282 

The  Mean  Effective  Pressure  283 

To  Space  the  Ordinates  285 

To  Calculate  the  Indicated  Horse-Power  285 

Theoretical  Economy  286 

How  TO  Calculate  Theoretical  Rate  of  Water  Consumption  288 
Indicator  Diagrams   291-320 

Formula  for  Finding  the  Theoretical  Clearance  when  the  Scale  is 
known  316 

Formulae  for  Finding  the  Horse-Power  of  Steam-Engines  by  Indi- 
cator Diagrams  318 

Another  Formula  319 

What  Indicator  Diagrams  Show,  and  How  they  Show  it     .  321 

The  Planimeter  323 

Steam-Engine  Economy  325 

Location  of  Steam-Engines  329 

The  Porter- Allen  High-Speed  Engine  330 

Questions  334 

PART  FIFTH. 

Condensers  .      .      .      .•  338 

Table  showing  the  Force  with  which  Uncondensed  Steam  arising  from 
Water  in  Condenser  resists  Ascent  or  Descent  of  Piston,  according 
to  its  Temperature  341 

IRelative  Quantity  of  Injection- Water  required  to  Condense 
A  Certain  Volume  of  Steam   .      ,  342 


xvi 


CONTENTS. 


PAGE 

The  Injector  Condenser  345 

Independent  Condenser  and  Air-Pump  346 

The  Vacuum       .    •  348 

Table  showing  Vacuum  in  Inches  of  Mercury  and  Pounds  Pressure 

per  Square  Inch   349 

Air-Pumps    ............  353 

The  Salinometer  360 

Table  showing  Proportion  of  Salt  in  Water  of  different  Seas    .       .  362 

Table  showing  Boiling-Point  of  Salt  Water  at  different  Degrees  of 
Density,  when  the  Barometer  stands  at  30  Inches   ....  362 
The  Barometer  364 

Table  showing  Weight  of  Atmosphere  per  Square  Inch  corresponding 

with  different  Heights  of  Barometer  365 

Thermometers  365 

Marine  Steam-Engine  Register  367 

Spring-,  Mercury-,  Syphon-,  and  Vacuum-Gauges  .  .  .  369 
The  Mariner's  Compass  373 

Table  of  Khumbs,  or  Points  of  the  Co pass      .....  374 

Table  showing  Magnitudes  and  Velocities  of  the  Planets  .  .  .  375 
Technical  Terms  and  Definitions  Used  in  Navigation  .       .  376 

Table  of  Miles  as  Measured  by  Various  Nations  ....  382 
Length  of  Days  in  Different  Countries  382 

Table  of  Sailing  Distances  from  New  York  to  different  Parts  of  the 
World,  in  Geographical  Miles  383 

Table  of  Latitude  and  Longitude  of  Places  384 

Table  showing  Time  at  different  Places  when  it  is  12  o'clock  Noon  at 
New  York       .       .  385 

Table  of  Miles  and  Knots,  Knots  and  Miles  386 

Marine  Signals  ,  386 

Marine  Whistle-Signals  389 

Marine  Bell-Signals   .       .       •       .  390 

Light  Signals  for  Ocean  Steamships  390 

Railroad  Signals  391 

Train  Signals  o      .  392 

Enginemen's  Signals   393 

Conductors'  Signals  394 

Signals  by  Lamp  394 

The  Screw-Prqpeller  394 

The  Paddle-Wheel   ..........  396 

Pumps  400 

Injectors  406 


CONTENTS.  Xvil 

PAGE 

William  Sellers  &  Co.'s  Injectok  408 

Table  showing  Steam-Pressure  required  to  Lift  and  Deliver  Water 

with  Sellers'  Fixed-Nozzle  Lifting  Injector  412 

Sellers'  Non-Adjusting  Fixed-Nozzle  Injector,  with  Lifting 

Attachment,  for  Stationary  Boilj:rs  412 

Table  showing  Maximum  and  Minimum  Delivery  of  Sellers'  Self- 
Adjusting,  1876,  Injector  No.  6  ;  Temperature  of  Delivered  Water; 
Pressure  against  which  Injector  delivers  Water,  and  Highest  Tem- 
perature of  Feed  admissible;  Water  flowing  to  Injector  under  15 

Inches  Head  ;  Waste- Valves  Shut  416 

Table  of  Capacities  of  Sellers'  Injectors  417 

Temperature  of  Feed-Water       ........  417 

Kue's  "Little  Giant"  Injector  418 

Table  of  Capacities  of  Rue's    Little  Giani"  Injector        .       .       .  420 

Friedman's  Injector   ...  420 

Table  of  Capacities  of  Friedman's  Injectors       .....  422 

The  Keystone  Injector  422 

The  Keystone  Lifting  Injector  423 

The  Eclipse  Injector  424 

The  Clipper  Injector  -       .  426 

Table  of  Capacities  of  Clipper  Injectors  428 

The  Inspirator  430 

Table  of  Capacities  of  the  Hancock  Inspirator  432 

Instructions  for  Setting  up.  Properly  Attaching  and  Ad- 
justing Injectors  432 

The  Ejector  or  Lifter  434 

Jamison's  Steam  Water-Ejector  435 

Table  of  Capacities  of  Jamison's  Steam  Water-Ejector  .  .  .  435 
Questions  436 

PART  SIXTH. 

Steam-Boilers  442 

Bursting  Pressure  of  Cylindrical  Stea^i-Boilers    .       .      .  448 

KuLES   451,  452,  468 

Boiler-Stays   453 

Stay- Bolts  454 

Table  showing  the  Breaking  Strain  of  Iron  and  Copper  Stay- Bolts    .  455 

Scale  in  Steam-Boilers  455 

Foaming  in  Marine-Boilers  457 

Priming  45S 

2*  B 


XVIU  CONTENTS. 

PAGE 

Corrosion,  and  its  Analogy  to  Combustion  460 

Manual  and  Mechanical  Firing  461 

Technical  Terms  applied  to  Firing  462 

Technical  Terms  employed  in  Kelation  to  Boilers.  .  462 

Friction  of  Eiveted  Seams  463 

Calking  463 

Steam-Boiler  Explosions  464 

Safety- Valves  465 

Draught  in  Chimneys  469 

Smoke  473 

Feed- Water  Heaters  474 


Table  showing  Units  of  Heat  required  to  Convert  One  Pound  of 
Water,  at  the  Temperature  of  32°,  into  Steam  at  different  Pressures  475 
Technical  Terms  applied  to  Adjuncts  of  the  Steam-Boiler  476 
Instructions  for  the  Care  and  Management  of  Steam-Boilers  478 


Boiler  Materials     .       .  480 

Definitions  of  the  Technical  Terms  applied  to  the  Differ- 
ent Kinds  of  Boiler-Plate  486 

Questions  491 

PART  SEVENTH. 

Air  496 

Table  of  Altitudes  above  Sea-Level,  and  the  corresponding  Atmos- 
pheric Pressures,  deduced  from  the  Observations  of  the  Hayden 

Expedition  to  the  Eocky  Mountains  498 

Table  showing  the  Force  of  the  Wind  in  Pounds  per  Square  Foot  at 

different  Velocities   •       .       .  499 

Horse-Power  of  Wind-Storms  499 

Altitude  of  the  Highest  Mountains  in  the  World       .      .  500 

Highest  Waterfalls  in  the  World  500 

Table  showing  Relative  Volumes  of  Air  at  various  Temperatures     .  501 
Technical  Terms  which  are  applied  to  Fluids  and  Vapoks, 
AND  WHICH  Bear  a  Certain  Relation  to  the  Steam-Engine  502 

Fuel  503 

Heat   507 

Table  showing  the  Latent  Heat  of  various  Substances  .  .  .  508 
Table  showing  the  Radiating  Properties  of  different  Substances .  .  508 
Table  showing  the  Effects  of  Heat  upon  different  Bodies  .  .  .  508 
Table  showing  the  Specific  Heat  of  different  Substances  .  .  .  509 
Table  showing  the  Relative  Weight  and  Volume  of  different  Gases  .  509 


CONTENTS.  xix 

PAOK 

Table  showing  the  Non-conducting  Pro{)ertiefi  of  different  Materials 

at  Even  Thickness  510 

Combustion  510 

Table  showing  the  Total  Heat  of  Combustion  of  various  Fuels  .  .512 

Water  514 

Table  showing  the  Quantity  and  Weight  of  Water  in  Pipes  One 
Fathom  in  Length  (6  Feet),  and  of  different  Diameters  from  1  to 

12  Inches  518 

Table  showing  the  Quantity  of  Water  per  Lineal  Foot  in  Pumps  or 

Vertical  Pipes  of  different  Diameters  519 

Table  showing  the  Weight  of  Water  at  different  Temperatures  .       .  520 
Table  showing  the  Boiling-Point  for  Fresh  Water  at  different  Alti- 
tudes above  Sea-Level   520 

Table  showing  the  Capacity  of  Cisterns  and  Tanks,  Computed  in  Bar- 
rels of  31^  Gallons  521 

Table  showing  the  Power  required  to  raise  Water  to  different  Alti- 
tudes, varying  from  1  Foot  to  20,000  Feet      .   '   .       .       .  .522 
Table  showing  the  Capacity  of  Cisterns  in  Gallons  for  each  10  Inches 

in  Depth  523 

Table  showing  the  Daily  average  Number  of  Gallons  of  Water  per 
Individual  in  different  Cities,  including  the  Quantity  Used  for 
Manufiicturing  Purposes,  Fountains,  etc.  .  ....  524 

Vapors  525 

Table  showing  the  Temperature  of  Saturated  Vapor  in  Atmospheres, 

according  to  Zeuner  525 

Tiable  showing  the  Pressure  and  Temperature  of  the  Vapors  of  Water 

from  32°  to  400°  Fah  526 

Gases     .      .  530 

Technical  and  Chemical  Terms  as  applied  to  Substances  that 
Bear  Relations  to  the  Steam-Engine  both  in  Theory  and 

Practice  534 

Areas  of  Circles  536 

Rules  538 

Significations  of  Signs  Used  in  Calculations   ....  542 

The  Cipher  542 

Table  of  Diameters  and  Areas  of  Small  Circles  .....  543 
Table  containing  the  Diameters,  Circumferences,  and  Areas  of  Circles 
from  y\  of  an  Inch  to  100  Inches,  advancing  by  -^^  of  an  Inch  up 
to  10  Inches,  and  by  J  of  an  Inch  from  10  to  100  Inches  .  544 

Table  of  Logarithms  of  Numbers  from  0  to  1000  ....  555 
Table  of  Hyperbolic  Logarithms       ...       ....  557 


XX  CONTENTS. 

PAGE 

Peculiarities  of  Multiplicatton   ,      .      .      ,      „  ,  560 

Decimal  Arithmetic  ,      ,      .      .      .  560 

Table  of  Vulgar  and  Decimal  Fractions  of  an  Inch   ....  561 

Table  of  Common  and  Decimal  Fractions  561 

Units  562 

Table  showing  all  the  Units  of  Length  Kecognized  in  England  since 

the  16th  Century   565, 

Atoms  and  Molecules  566 

Table  of  Squares,  Cubes,  and  Square  and  Cube  Boots  of  all  Numbers 

from  1  to  620    567 

The  Wetherill  Corliss  Engine  583 

Emergencies  584 

Questions    585 

PART  EIOHTH. 

Lexicon  of  Definitions  of  Central,  Mechanical,  and  Dynam- 
ical Forces  587 

Metals  and  Alloys  612 

Table  of  Mineral  Substances  and  their  Chemical  Equivalents  .  .612 
Table  showing  the  Heat-Conducting  Properties  of  Different  Metals  .  614 
Table  showing  the  Tenacity  or  Tensile  Strength  of  Different  Metals  .  614 
Table  showing  the  Proportion  of  Carbon  in  the  various  Grades  of 

Iron  and  Steel  *  .615 

Alloys  and  Compositions  616 

Solder  617 

Table  showing  the  Average  Crushing  Load  of  different  Materials,  or 

the  Weight  under  which  they  will  Crumble  617 

Table  showing  the  Tensile  Strength,  or  the  Strain  that  will  Pull  dif- 
ferent Metals  Asunder  on  a  Straight  Pull  618 

Table  showing  the  Tensile  vStrength  of  different  Kinds  of  Wood  .  618 
Table  showing  the  Weight  of  Castings  by  Weight  of  the  Patterns  .  620 
Table  showing  the  Shrinkage  of  Castings  of  different  Metals  .  .  620 
Table  showing  the  Weight  and  Bulk  of  different  Substances  in  Cubic 

Feet,  Pounds,  and  Tons  620 

Table  showing  the  Weight  of  different  Metals  per  Cubic  Foot  .  .  621 
Table  showing  the  Actual  Extension  of  Wrought-Iron  at  various 

Temperatures  621 

Table  showing  the  Linear  Dilatation  of  Solids  by  Heat     .       .       .  622 
Table  deduced  from  Experiments  on  Iron  Plates  for  Steam-Boil ers, 
by  the  Franklin  Institute,  Philada.  623 


CONTENTS. 


xxi 


PAGE 

Table  showi;ig  the  Strength  of  Copper  Boiler-Plates  at  different  Tem- 
peratures, deduced  frarn  Experiments  by  the  Franklin  Institute  of 
Phila.    The  Standard  Strength  at  32°  being  32,800  Pounds  per 

Square  Inch  623 

Table  showing  the  Weight  of  Cast-Iron  Balls  from  3  to  13  Inches  in 

Diameter  624 

Table  showing  the  Weight  of  Cast-Iron  Plates  per  Superficial  Foot 

as  per  Thickness  624 

Table  showing  the  Weight  of  Eound  Iron  from  i  an  Inch  to  6  Inches 

in  Diameter,  1  Foot  Long  625 

Table  showing  the  Weight  of  Boiler-Plates  1  Foot  Square  and  from 

of  an  Inch  to  an  Inch  Thick   .  626 

Table  showing  the  Weight  of  Square  Bar-Iron,  from  2  an  Inch  to  6 
Inches  Square,  1  Foot  Long    ........  626 

Table  showing  the  W^eight  of  Cast-iron  Pipes,  1  Foot  in  Length,  from 

J  Inch  to  Ij  Inches  Thick  and  from  3  Indies  to  24  Inches  Diameter  627 
Tables  showing  the  Standard  W^eights  of  Cast-iron  Water-  and  Gas- 
Pipes   628 

Table  showing  the  Tensile  Strength  of  various  Qualities  of  American 

and  English  Cast-Iron  628 

Table  showing  the  Tensil«  Strength  of  various  Qualities  of  American 

Wrought-Iron  629 

Table  showing  the  Results  of  Experiments  made  on  difierent  Brands 

of  Boiler-Iron  at  the  Stevens  Institute  of  Technology,  Hoboken,  N.  J.  630 
Table  giving  the  Proportions  of  the  United  States  or  Sellers'  Stand- 
ard Threads  for  Screws,  Nuts,  and  Bolts  6itl 

Speed,  Power,  Capacity,  and  Dress  of  Millstones     .      .      .  632 
Speed  of  Circular  Saws  .      .      .      .      .      .      .      .      .  632 

Table  of  Coefficients  of  Friction  between  Plane  Surfaces  .  .  .  633 
N on-Conducting  Covering  for  Steam-Boilers  and  Pipes  .      .  634 

Belting  637 

Gearing  645 

Fitchburg  Steam-Engine  Company's  Automatic  Cut -Off  Engine  648 

The  Improved  Circulating  Salinometer  650 

Crosby's  Adjustable  ^'Pop"  Safety-Valve  654 

The  Improved  Planimeter  656 

Crosby's  Improved  Steam-Pressure  Hydraulic,  Combination, 

Vacuum,  and  Self-Testing  Gauges  657 

The  Atlas  Corliss  Engine  663 

Questions   .      .  668 

Index  673 


LIST  OF  ILLUSTRATIONS. 

PAGE 

The  Centennial  Corliss  Engine,  24 

Wright's  Automatic  Cut-Off  Engine,  ......  36 

Woodbury,  Booth  &  Pryor's  Automatic  Cut-Off  Engine,      .  53 

Double-Slide  Valves,  55 

Semi-Rotary  Valves,  55 

The  Brown  Automatic  Cut-Off  Engine,  89 

Harris  Corliss  Engine,  93 

Modern  Marine  Compound  Engine,  110 

Section  of  Marine  .Compound  Engine,  Ill 

The  Woodruff  &  Beach  Automatic  Cut-Off  High-Pressure 

Engine,  125 

The  Putnam  Machine  Company's  Automatic  Cut-Off  Engine,  139 
The  Greene  Automatic  Cut- Off  High-Pressure  Engine,       .  150 

The  Babbitt  &  Harris  vSteam-Piston,  167 

Piston,  Connecting-Eod,  and  Crank  Connection,  ....  175 

The  Reynolds  Corliss  Engine  178 

The  Crank,  183 

The  Link,  184 

Valve-Gear,  ♦  199 

The  Watertown  Automatic  Cut-Off  Engine,     ....  195 

The  Waters  Governor,  197 

The  Shive  Governor,   .199 

Reversing-Gear,  203 

Diagrams  of  Slide- Valve,       .......  204-213 

The  Wheelock  Automatic  Cut-Off  Engine,       ....  215 

Poppet- Valves,  223 

Slide- Valves,  230 

The  Wells  Two-Piston 'Balance-Engine,  233 

The  Wardwell  Valveless  Engine,  241 

The  Steam-Engine  Indicator,  251 

Thompson's  Indicator,  251 

Crosby's  Improved  Indicator,  ......      c      .  255 

Section  of  Crosby's  Indicator,       .......  257 

Tabor's  Indicator,  260 

Section  of  Tabor's  Indicator,  261 

Richards'  Parallel  Motion  Indicator,  275 

Indicator  Diagrams,   291-320 

The  Planimeter,   323,  656 

Diagram  Measured  by  the  Planimeter,  325 


xxii 


LIST   OF  ILLUSTRATIONS. 


XXIU 


PAGE 

The  Porter-Allen  High-Speed  Engine,      .      ,      .      .      .  331 

Surface  Condenser  338 

The  Injector  Condenser,  344 

Independent  Condenser  and  Air-Pump,  348 

Independent  Air-  and  Circulating-Pump,  352 

Section  of  a  Marine  Air-Pump,  353 

Independent  Marine  Circulating-Pump,  358 

Marine  Wrecking-Pump,  359 

The  Salinometer,  »      .       .       .  360 

The  Hotwell  Thermometer,  366 

The  Uptake  Thermometer,  366 

Marine  Steam-Engine  Kegister,  367 

Spring  Steam-Gauges,   369-371 

Marine  Whistle-Signals,  389 

Pumps,  401 

William  Sellers  &  Co.'s  Injectors,  409 

Rue's  "Little  Giant"  Injector,     ......  418,419 

Friedman's  Injector,   .  .421 

The  Keystone  Injector,  422 

The  Eclipse  Injector,  425 

The  Clipper  Injector,     .........  426 

Mack's  Fixed-Nozzle  Injector,  429 

The  Inspirator,   430,  431 

The  Ejector  or  Lifter,  434 

Jamison's  Steam  Water-Ejector,  435 

Water-Tubular  Marine-Boiler,  442 

Fire-Tubular  Marine- Boiler,  443 

Direct  Flue  and  Eeturn  Tubular  Marine-Boiler,  .  .  .  446 
Methods  of  Bracing  Marine  Steam-Boilers,  ....  450 
The  Buckeye  Automatic  High-Pressure  Cut-Off  Engine,      .  489 

Diagrams  of  Circles,   537,  538 

The  Wetherill  Corliss  Engine,    .......  582 

Steam-Joints,   634 

Back  View  of  the  Fttchburg  Automatic  Cut-Off  Engine,     .  647 

The  Fitchburg  Governor,  649 

Circulating  Salinometer,       ........  651 

Crosby's  Adjustable  "Pop"  Safety^- Valve  .....  654 

Exterior  View  of  Crosby's  Steam  Gauge,  .      .      .      .      .  658 

Interior  View  of  the  Original  Bourdon  Steam  Gauge,       .  658 

Interior  View  of  Crosby's  Steam  Gauge,  659 

Crosby's  Self-Testing  Steam  Gauge,  660 

Crosby's  Vacuum  Gauge,  660 


24 


THE 


ENGINEER'S 

PART  FIRST. 

The  Centennial  Corliss  Engines. 

The  Centennial  Corliss  Engines  were  beam-engine&  of  the  Cor- 
liss type,  with  all  the  latest  improvements,  and  nominally  of  700 
horse-power  each,  or  1400  horse-power  together.  The  cylinders 
were  40  inches  in  diameter,  with  10  feet  stroke.  They  were  pro- 
vided with  air-pumps  and  condensers,  consequently  they  could  be 
worked  either  condensing  or  non-condensing,  and  were  intended 
to  work  with  from  25  to  80  lbs.  of  steam  pressure,  according  to 
the  requirements  of  the  exhibition.  The  gear  fly-wheel  was  30 
feet  in  diameter,  2  foot  face,  and  weighed  56  tons;  it  was  un- 
doubtedly the  largest  gear-wheel  ever  made.  The  pinion  that 
was  driven  by  this  large  fly-wheel  was  a  solid  casting  10  feet  in 
diameter,  weighing  17,000  lbs.,  and  was  the  largest  ever  made. 
The  main  frame  was  A  shaped,  having  the  journals  for  the  beam- 
centres  on  the  top,  and  the  legs  bolted  to  the  bottom  of  the  cylin- 
der on  one  side,  and  to  the  main  crank-shaft  journals  on  the 
other. 

3  25 


26 


THE   engineer's  HANDY-BOOK. 


The  walking-beams  were  of  the  web-beam  pattern,  and  made 
of  cast-iron,  and,  in  consequence  of  th#r  peculiar  shape,  detracted 
very  much  from  the  general  appearance  of  the  engine.  They 
were  9  feet  wide  at  the  centre,  and  27  feet  long,  each  weighing 
22,000  lbs.  The  cross-head  guides  extended  from  the  upper  cylin- 
der-heads to  the  top  gallery,  and  were  provided  with  screws  by 
which  they,  as  well  as  the  cylinder-heads,  might  be  lifted  to  admit 
of  access  to  the  pistons.  The  piston-rods,  which  were  made  of 
steel,  were  6}  inches  in  diameter.  The  cranks  were  highly  fin- 
ished, and  weighed  10,000  lbs.  each.  The  connecting-rods  were 
24  feet  long.  The  steam-valves  received  their  motion  from  a 
wrist-plate  and  a  system  of  levers  similar  to  those  employed  in 
the  ordinary  Corliss  engine,  and  the  releasing  gear  for  them  was 
entirely  original,  and  very  ingenious,  though  the  exhaust-valves 
ended  their  vibrations  by  an  abrupt  kick  or  jerk. 

The  height  of  the  engines,  from  the  floor  to  the  top  of  the  walk- 
ing-beams, was  39  feet,  and  their  weight,  with  all  their  adjuncts 
and  attachments,  was  over  700  tons.  The  engines  were  supplied 
with  steam  by  20  upright  Corliss  boilers,  of  70  horse-power  each. 
The  main  steam-pipe  was  18  inches  in  diameter  and  320  feet  long. 
The  engines  rested  on  a  platform  55  feet  in  diameter,  and  3  J  feet 
above  the  floor  of  the  building.  The  top  of  the  frame  was  sur- 
rounded by  a  circular  gallery,  which  aflTorded  access  to  the  beams 
and  all  the  upper  works  ;  this  gallery  was  reached  by  a  semi-cir- 
cular stairway  on  each  side.  These  engines  were  objects  of  general 
interest  and  curiosity,  and  served  to  illustrate  the  wonderful  de- 
velopment of  the  steam-engine  in  this  country,  and  the  amount 
of  inventive  genius  that  must  have  been  devoted  to  its  improve- 
ment. 

After  the  close  of  the  Centennial  they  were  taken  down  and 
removed  to  the  builder's  establishment.  Providence,  K.  I.,  where 
they  remained  until  recently,  when  they  were  sold  to  the  Pull- 
man Palace  Car  Co.  for  the  purpose  of  furnishing  the  motive- 
power  for  their  works,  near  Chicago,  and  also  the  power  for  the 
Allen  Paper  Car-Wheel  Works  adjoining. 


THE  engineer's  HANDY-BOOK. 


27 


steam  Engineering. 

Steam  Engineering  has  assumed  such  vast  proportions  as 
an  agent  of  modern  progress  and  civilization,  that  it  has  given 
birth  to  a  profession  whose  scope  and  functions  are  not  yet  very 
clearly  defined.  The  engineer's  duty,  in  the  performance  of  his 
daily  routine,  involves  the  application  of  the  laws  of  Nature  in 
various  ways,  to  understand  and  explain  which  require  a  wide 
range  of  scientific  knowledge.  While  there  are  to  be  found  in 
the  profession  men  whose  intelligence  and  acquirements  would 
shed  lustre  on  any  calling,  there  are  others  who,  by  their  loose  dis- 
regard of  correct  rules,  show  that  they  are  laggard  in  the  acquisi- 
tion of  that  real  knowledge  so  essential  to  men  in  their  profession. 
This  is  to  be  regretted,  in  view  of  the  vast  amount  of  property 
and  the  great  number  of  valuable  lives  intrusted  to  their  care, 
both  on  sea  and  land.  But  whenever  any  attempt  is  made  to  induce 
engineers  to  qualify  themselves  for  their  calling,  the  effort  is  met 
with  the  old  stereotyped  question  regarding  the  relative  merits  of 
theoretical  and  practical  engineers,  or  the  comparative  value  of 
theory  and  practice.  The  practical  men,  who  have  no  theoretical 
knowledge,  scoff  at  the  theorists,  and  the  latter  sneer  at  the  former. 
It  requires  very  little  experience  on  the  one  hand,  and  not  much 
study  on  the  other,  to  show  that  each  are  equally  important,  only 
in  different  ways.  Both  parties  should  know  that  "  Theory  and 
Practice  make  perfect.''  Theory,  together  with  practical  experi- 
ence, will,  without  doubt,  enable  men  to  excel  in  whatever  work 
they  may  undertake.  Therefore,  it  should  be  the  highest  ambition 
of  engineers  to  combine  theory  with  practice,  and  prove  the  one 
by  the  other. 

This  object  may  be  effected  by  devoting  a  portion  of  their 
leisure  hours  to  study,  and  by  pursuing  a  systematic  course  of 
self-culture.  The  engineer  whose  early  training  has  been  neglected, 
and  who  is  now. debarred  from  the  advantages  of  a  good  educa- 
tion, need  have  no  cause  for  despondency,  because  the  extra  exer- 
tion and  effort  required  to  educate  himself  will  confer  advantages 


28  THE  engineer's  handy-book. 

of  their  own,  which  the  routine  work  of  a  school  cannot  develop. 
Of  course,  there  are  men  in  this,  as  in  all  other  callings,  who  will 
fail,  however  much  they  may  try  to  accomplish  in  the  way  of 
educating  themselves.  This  arises  from  the  fact  that,  though 
morally  all  men  may  be  equal,  intellectually  they  never  can  be 
so.  Consequently,  the  ability  of  men  to  educate  themselves  varies 
in  proportion  to  the  amount  of  natural  intelligence  they  possess. 
But  in  any  case,  study  gives  quickness  of  apprehension,  enables  a 
man  to  profit  by  all  the  recorded  experience  of  others,  develops 
a  power  of  appreciation  and  concentration,  enforces  exactness  and 
accuracy,  and,  if  properly  directed,  teaches  men  to  classify  facts, 
make  proper  deductions  and  reason  logically.  The  knowledge 
acquired  from  the  study  of  books  is  of  inestimable  value  to  the 
young  engineer,  as  without  it  he  can  never  be  thoroughly  qualified 
for  the  duties  of  his  profession,  since  he  will  be  lacking  in  certain 
definite  information  which  can  only  be  obtained  from  them,  owing 
to  the  want  of  which  he  is  almost  sure  to  be  not  only  narrow- 
minded,  but  also  very  slow  to  receive  new  ideas  or  to  estimate  the 
proper  value  of  old  ones. 

Such  persons,  if  occupying  positions  in  which  they  exercise 
authority,  are  very  apt  to  become  intolerant  of  other  people's 
opinions,  to  assume  that  all  knowledge  begins  and  ends  with  them- 
selves, or  with  what  they  have  learned,  and  to  over-estimate  their 
own  ability.  They  are  apt  to  be  self-conceited,  a  quality  which 
too  many  in  every  calling  possess,  mistaking  it  for  an  independent 
spirit.  One  of  the  commonest  excuses  for  ignorance  is  the  stereo- 
typed expression,  I  am  too  old  to  learn."  This,  if  made  in  sin- 
cerity, is  a  great  mistake,  as  it  is  a  false  pride  which  neglects  an 
opportunity  to  learn  because  it  comes  late  in  life,  and  it  is  a  false 
fear  which  shrinks  from  an  efibrt  on  account  of  its  diflSculty.  One 
fact  very  important  to  be  considered  in  this  connection,  is,  that 
knowledge  throws  light  upon  itself;  and  that  it  is  the  first  step 
only  that  must  be  taken  gropingly,  as  it  were  in  the  dark,  as  the 
bugbears  in  such  cases,  like  shadows,  vanish  the  moment  they  are 
boldly  approached,  and  will  be  found  to  be  mere  shadows  after 


THE   ENGINEER'S  HANDY-BOOK. 


29 


all.  Truths  are  in  the  main  simple  and  easy  to  be  understood, 
and  are  daily  being  brought  more  within  the  grasp  of  the  most 
ordinary  comprehension  by  means  of  good  books,  which  may  be 
had  at  trifling  cost.  It  is  frequently  asserted,  by  members  of  this 
calling,  that  they  are  no  book-engineers  ;  which  statement  betrays 
their  ignorance  of  the  manner  in  which  some  of  the  most  valuable 
books  on  the  steam-engine  originated.  They  were  written  by  en- 
gineers of  experience,  who  wished  to  advance  their  profession,  and 
who  thought  that,  if  their  predecessors  could  commence  their 
studies  in  their  young  days,  they  themselves  might  advance  and 
improve  still  further,  leaving  the  benefit  of  their  experience  to 
posterity ;  the  art  would  therefore  advance  with  the  age.  As  much 
information  may  be  learned  in  a  few  weeks  from  the  works  which 
they  have  left  us,  as  had  taken  them  years  of  observation  and  trial 
to  ascertain. 

Most  of  the  abuses  connected  with  steam  engineering  have 
arisen  from  two  causes,  viz.,  avarice  and  ignorance ;  avarice  on 
the  part  of  owners  of  steam-engines  and  steam-boilers,  who  enter- 
tain the  idea  that  cheap  steam-engines  and  boilers  might  be 
managed  by  a  class  of  persons  who  were  willing  to  work  for  very 
low  wages;  and  ignorance  on  the  part  of  those  who  claimed  to  be 
engineers,  but  who  were  only  men  of  all  work,  or  at  best  mere 
laborers  in  the  treadmill  of  routine  (stoppers  and  starters).  It  is 
evidently  one  of  the  greatest  mistakes  connected  with  the  use  of 
machinery,  to  intrust  its  care  and  management  to  persons  of  in- 
ferior judgment,  as  a  competent  engineer,  who  could  command 
good  wages,  would  probably  save  three  times  the  difference  by  his 
judgment  and  skill  in  its  proper  maintenance.  If  engineers  wish 
to  raise  the  standard  of  their  profession  to  what  it  ought  to  be, 
and  command  remunerative  compensation  for  their  services,  they 
may  do  so  by  educating  themselves,  and  not  otherwise.  It  will 
not  do  for  them  to  shrug  their  shoulders,  and  claim  to  be  "  prac- 
tical men,"  who  reject  theories,  because  it  is  well  known  that  such 
men  have  become  a  nuisance  in  every  branch  of  mechanics,  being 
the  least  progressive,  the  least  enlightened,  and  the  most  stubborn 
3* 


30 


THE   ENGINEER'S  HANDY-BOOK. 


in  the  assertion  of  their  views ;  because  their  minds  are  cramped, 
and  will  not  allow  of  either  the  substitution  or  the  admission  of 
ideas  different  from  their  own,  however  crude  and  primitive  they 
may  be. 

The  engineer  of  the  ferry-boat  Westfield  belonged  to  this  class. 
Although  he  had  been  fourteen  years  an  engineer  on  tug-  and 
ferry-boats,  he  was  unable  to  tell  the  figures  on  the  steam-gauge; 
and,  at  the  investigation  that  followed  the  frightful  disaster  that 
occurred  on  board  that  ill-fated  boat,  on  being  asked  what  a  va- 
cuum was,  answered  that  "he  thought  it  was  foul  air."  It  was  also 
in  evidence  that  the  chief  engineer  of  the  line  on  which  he  was 
employed  was  equally  wanting  in  that  practical  knowledge  that 
ought  to  be  possessed  by  a  person  occupying  his  position.  These 
may,  perhaps,  be  said  to  be  extreme  cases,  but  they  will  only 
prove  to  be  so  when  it  can  be  shown  that  there  are  not  hundreds 
of  others  occupying  the  same  positions  who  are  not  much  better 
informed.  No  man  is  practical  unless  he  proves  practice  by 
theory  and  theory  by  practice,  and  who  attaches  any  importance 
to  statements  not  sustained  by  facts.  Such  men  can  always  be 
distinguished  from  the  self-styled  "  practical  men,"  by  an  unassum- 
ing manner,  and  by  rarely  making  any  pretensions;  when  ex- 
pressing their  opinions,  they  have  a  tendency  to  underrate  their 
own  ability,  not  because  they  pretend  to  be  less  capable  than  they 
really  are,  but  (as  so  many  men  have  become  pretentious  in  their 
manners  and  expressions)  because  they  fear  they  may  be  con- 
sidered as  belonging  to  that  class.  On  the  other  hand,  the  self- 
styled  variety  are  continually  thrusting  themselves  forward,  and 
can  easily  be  distinguished  by  the  profuse  use  of  the  pronoun  "I,' 
which  is  evidence  of  conceit  or  ignorance,  or  perhaps  of  both. 

A  great  deal  has  been  said  and  written  on  thesubject  of  licens- 
ing engineers,  but  there  seems  still  to  be  as  great  a  diversity  of 
opinion,  as  to  the  benefit  to  be  derived  from  it,  as  on  any  other 
connected  with  the  profession.  Many  engineers  are  of  the  opinion 
that,  in  consequence  of  the  loose  and  uncertain  way  in  which 
examinations  for  licenses  are  now  conducted,  a  law  that  would 


THE   ENGINEER\s  HANDY-BOOK. 


31 


require  every  engineer  to  submit  to  a  rigid  examination,  would 
prevent  all  but  first-class  men  from  being  employed  as  engineers. 
But  while  all  agree  that  there  should  be  a  license  law  to  reach  all 
classes  of  engineers,  there  are  more  formidable  difficulties  to  be 
overcome  in  the  impartial  execution  of  such  a  law  than  appear 
at  first  sight.  In  the  first  place,  it  would  be  almost  impossible  to 
place  the  office  of  examiner  or  inspector  beyond  the  reach  of 
political  influence,  consequently  his  decisions  would,  in  many  in- 
stances, be  likely  to  be  influenced  by  partisan  feelings.  The  next 
objection  is,  that  it  is  not  in  the  power  of  any  man  to  determine, 
with  any  certainty,  the  ability  of  an  engineer  by  any  theoretical 
examinations.  The  candidate  should  be  required  to  show  his 
ability  by  practical  demonstration.  Another  point  is,  that  it  is 
very  difficult  for  a  stranger  to  judge  a  man's  qualifications  as  an 
engineer,  with  any  degree  of  certainty,  in  comparison  with  those 
who  are  in  daily  intercourse  with  him,  which  goes  to  show  that, 
unless  it  is  possible  to  determine  to  a  certainty  a  man's  ability  as 
an  engineer,  the  license  is  of  no  value.  The  execution  of  any 
license  law  to  produce  beneficial  and  satisfactory  results  should 
only  be  intrusted  to  a  board  of  engineers,  composed  of  theoret- 
ical, practical,  and  painstaking  men  —  men  who  have  performed 
all  the  duties  incidental  to  the  calling  of  an  engineer. 

For  this  reason  examinations  ought  to  be  conducted  in  the  engine- 
and  boiler-rooms,  where  the  persons  applying  for  certificates  are 
employed.  In  that  case,  there  would  be  an  opportunity  to  test  the 
candidate's  practical  knowledge  of  everything  connected  with  the 
engine  and  boilers  under  his  charge.  There  can  be  no  reason  why 
persons,  whose  duty  it  is  to  inquire  into  the  capabilities  of  persons 
having  charge  of  steam-engines  and  boilers,  should  not  do  so  on 
the  premises,  or  on  the  vessels  on  which  they  are  employed,  as  well 
as  10  have  them  go  several  miles,  and  frequently  into  another 
county,  for  that  purpose.  Examinations  ought  to  be  uniform  in 
all  localities ;  as,  where  the  subjects  embraced  in  the  examination 
differ  iu  different  localities,  the  system  is  unjust. 


32 


THE   ENGINEER'S  HANDY-BOOK. 


There  are  thousands  of  instances  on  record  where  men,  having 
charge  of  engines  and  boilers  for  10  or  12  years,  have  secured  only 
a  second-  or  third-class  certificate,  simply  because  they  were  men 
of  limited  education,  and  could  only  imperfectly  express  what  they 
actually  knew ;  while  others,  who  could  furnish  no  positive  evi- 
dence of  ever  having  had  charge  of  an  engine  or  boiler,  and  who 
did  not  possess  any  of  the  qualifications  so  essential  to  an  engineer, 
obtained  first-class  certificates,  because  they  were  theorists  and 
good  mathematicians.  It  is  quite  common  to  find  blatant  indi- 
viduals, who  have  no  reputation  for  ability,  sobriety,  and  industry, 
parading  first-class  certificates,  which  they  obtained  because  they 
had  abundance  of  assurance,  while  many  practical  and  unas- 
suming men  are  almost  afraid  to  apply  for  a  certificate,  lest  they 
should  be  degraded  to  the  level  of  a  third  or  fourth  class  engineer. 
While  theorists  and  mathematicians  should  receive  their  due  meed 
of  merit,  it  would  seem  unjust,  so  far  as  the  awarding  certificates  is 
concerned,  to  place  them  above  the  men  who,  though  possessing  only 
a  limited  education,  had  shown  by  years  of  industry,  truthfulness, 
and  the  successful  pursuit  of  their  calling,  that  they  were  perfectly 
reliable  in  every  respect.  These  are  nice  points  to  decide,  partic- 
ularly when  it  has  to  be  done  by  one  man,  perhaps  without  any 
practical  experience. 

The  character  of  steam  engineering  can  never  be  much  ele- 
vated by  examinations  and  the  awarding  of  certificates  ;  the  only 
hope  for  this  lies  in  a  law  requiring  every  man  to  possess  an  ele- 
mentary knowledge  of  steam  and  steam  machinery  before  being 
permitted  to  take  charge  of  an  engine  and  boiler ;  as,  being  once 
recognized  as  engineers,  however  ignorant  men  may  be,  they,  as  a 
general  thing,  evince  a  lack  of  interest  in  acquiring  a  more  ex- 
tended knowledge  of  the  duties  of  their  calling.  They  frequently 
become  too  conceited  to  take  instructions  from  others,  or  even  to 
ask  a  question,  although  the  answer  might  put  them  in  possession 
of  a  fact  of  immense  value  to  them.  There  is  no  reason  why  one 
class  of  men  should  be  required  to  serve  a  regular  apprenticeship, 
and  even  to  devote  years  to  the  study  of  their  profession,  while 


THE   ENGINEER'S  HANDY-BOOK. 


33 


another  class  is  allowed  to  discharge  all  the  duties  of  a  calling 
equally  as  important,  with  scarcely  any  preparation. 

The  question  is  often  asked,  "Should  an  engineer  be  a  ma- 
chinist ? The  proper  answer  would  be,  not  necessarily  so ; 
there  is  no  reason  why  a  man  should  learn  two  trades  in  order  to 
follow  one.  Besides,  experience  has  shown  that,  though  ma- 
chinists are  in  some  instances  the  best  judges  of  things  that  may 
transpire  in  relation  to  steam  machinery,  they  are,  nevertheless, 
frequently  less  careful,  less  reliable,  and  less  ingenious,  than  those 
who  never  learned  a  regular  trade.  Moreover,  neither  Savary, 
Smeaton,  Watt,  Stephenson,  Fitch,  Fulton,  or  either  of  the  Ste- 
venses,  Baldwin,  or  Oliver  Evans  were  machinists.  An  engineer 
should  be  possessed  of  natural  talent,  should  be  ingenious  and 
able  to  discover  any  defect  that  may  occur  in  t^e  machinery  under 
his  charge,  be  able  to  take  up  the  lost  motion,  or  to  take  apart  and 
put  together  the  different  parts  of  an  engine. 

There  is  great  need  of  reform  in  the  use  of  the  term  engineer, 
as  a  customary  neglect  to  designate  to  what  branch  of  the  calling 
he  may  belong  gives  rise  to  much  inconvenience  and  confusion. 
A  bookseller  advertises  a  book  entitled  "  Hints  to  Young  En- 
gineers.'' Many  men  having  charge  of  steam-engines  order  the 
book  by  mail,  under  the  impression  that  it  contains  useful,  if  not 
valuable,  information  regarding  their  trade.  On  examination  it 
may  be  found  to  be  a  treatise  adapted  only  to  young  men  prepar- 
ing themselves  for  the  calling  of  civil  engineers,  not  making  a 
single  allusion,  or  having  any  bearing  whatever,  on  the  business 
in  which  the  party  ordering  it  was  engaged.  Another  author 
writes  a  book,  and  terms  it  "  an  Engineer's  Pocket-Book,"  intend- 
ing it,  of  course,  to  be  a  hand-book  for  all  classes  of  engineers, 
as  in  the  former  case;  although  it  may  contain  a  good  deal  of  val- 
uable and  useful  information,  it  will  be  found,  nevertheless,  too 
limited  to  meet  the  requirements  of  any  one  class,  as  it  would  be 
impossible  to  embody  such  information  in  a  book  of  ordinary  size, 
or  in  any  book  that  would  come  within  the  reach  of  persons  of 
limited  means;  nor  would  it  be  possible  for  any  author,  however 

C 


34 


THE   ENGINEER'S  HANDY-BOOK. 


learned  he  may  be,  to  elaborate  so  great  a  variety  of  subjects,  re- 
quiring, as  they  would,  scientific  accuracy  and  mathematical  pre- 
cision. 

It  is  not  uncommon  to  find  men  who  have  been  educated  as  civil 
engineers,  and  who  have  devoted  their  lives  to  the  pursuit  of  that 
calling,  presuming  to  write  treatises  for  the  instruction  of  mechan- 
ical engineers,  or  men  having  charge  of' steam-engines  and  steam 
machinery,  without  possessing  the  first  qualifications  for  such  an 
undertaking.  With  the  same  propriety,,  the  lawyer  might  write  a 
treatise  for  the  instruction  of  the  doctor,  and  vice  versa;  or  the 
doctor  might  attach  the  word  squire  to  his  name,  and  the  lawyer 
appropriate  the  title  of  M.D.  It  would  be  more  appropriate  to 
use  the  terms,  mechanical  or  steam  engineer,  civil  engineer,  hy- 
draulic engineer,  dynamic  engineer,  sanitary  engineer,  etc.,  as,  by 
the  general  adoption  of  these  terms,  persons  wishing  information 
in  regard  to  machinery,  bridges,  embankments,  or  hydraulics, 
might  consult  the  right  person,  instead  of  being  subjected  to  the 
annoyance  that  is  frequently  experienced  in  consequence  of  con- 
sulting or  engaging  the  services  of  the  wrong  party.  Engineers 
of  every  class  are  very  useful,  though  in  different  ways;  their  labors, 
next  to  that  rational  intellect  which  places  man  above  the  beast, 
have  conferred  on  mankind  the  greatest  boons,  and  the  monu- 
ments which  display  the  conceptions  of  their  genius  are  almost  as 
indestructible  as  the  firmament  or  the  ocean.  It  cannot  be  said 
of  the  engineer,  as  has  been  frequently  said  of  the  lawyer  or  the 
doctor,  that  if  mankind  could  do  without  him  it  would  be  well  for 
the  human  race. 

Facts  that  should  he  Borne  in  Mind  hj  Engineers. 

No  man  who  loves  exact  knowledge  can  fail  to  find  scope  for 
the  exercise  of  his  intellect  in  the  calling  of  an  engineer,  as  it  is 
adapted  to  men  of  the  most  opposite  temperaments.  Two  condi- 
tions alone  are  needed, —  the  man  must  love  his  work  and  have 
ability  to  perform  it. 


THE   ENGINEER\s  HANDY-BOOK. 


35 


There  is  no  royal  road  either  to  success  or  learning ;  the  nearest 
approach  to  such  a  thoroughfare  may  be  found  in  indefatigable 
study  and  reflection. 

A  smooth  sea  never  made  a  skilful  mariner.  Neither  do  unin- 
terrupted prosperity  and  happiness  qualify  a  man  for  usefulness. 
The  storms  of  adversity,  like  the  storms  of  the  ocean,  arouse  the 
faculties,  and  excite  invention,  prudence,  skill,  and  fortitude. 

The  very  nature  of  steam  engineering  calls  for  superior  intel- 
ligence in  those  on  whom  depend  the  care  and  management  of 
steam  machinery.  Engineers  should,  therefore,  prepare  themselves 
for  any  casualty  that  may  arise,  by  considering  possible  cases  of 
derangement,  and  deciding  in  what  way  they  would  act  should 
certain  accidents  occur. 

The  strength,  perfection,  and  durability  of  steam  machinery 
at  the  present  day  would  seem  to  insure  perfect  safety,  and  yet 
accidents  occur  when  least  expected,  for  which  no  amount  of 
mechanical  skill  or  forethought  could  provide.  It  is  in  such  cases 
that  the  coolness,  determination,  and  decision  of  the  engineer  may 
avert  a  great  calamity. 

The  wonderful  increase  in  the  size  and  speed  of  steamships 
and  locomotives  renders  it  absolutely  necessary  that,  with  a 
proper  regard  for  life  and  property,  they  should  be  in  charge  of 
men  of  well-ascertained  mental  and  physical  abilities,  as  inevi- 
tably, sooner  or  later,  at  a  critical  moment,  incapable  men  will  be 
found  wanting,  and  the  most  serious  consequences  result  from  their 
incapacity. 

Risks  of  collision,  of  stranding,  of  fire,  in  fact,  all  risks  per- 
taining to  steamships,  might  be  very  much  diminished  if  they 
were  placed  in  charge  of  intelligent  men. 

The  course  to  be  pursued  in  an  emergency  must  have  refer- 
ence to  particular  engines,  as  no  general  rules  can  be  given,  and 
every  engineer  should  decide  on  certain  measures  to  be  adopted 
in  any  emergency  in  which  he  may  be  called  upon  to  act,  where 
everything  may  depend  upon  his  energy  and  decision. 


38 


THE   ENGINEER'S  HANDY-BOOK. 


WRIGHT'S  AUTOMATIC  CUT-OFF  ENGINE. 

The  cuts  on  pages  36  and  37  represent  a  front  and  back  view  of 
Wright's  Automatic  Cut-off  high-pressure  engine,  the  bed-plate 
or  housing  of  which,  as  will  be  observed,  is  radically  different 
in  design  and  general  appearance  from  any  other  in  use  in  the 
country.  The  ordinary  guides  are  dispensed  with,  and  a  guiding- 
cylinder,  which  is  bored  out  on  a  line  with  the  centre  of  the  steam- 
cylinder,  for  the  direction  of  movement  of  the  cross-head,  substi- 
tuted. There  are  lateral  openings  in  the  sides  of  the  guiding- 
cylinder,  through  which  easy  access  to  the  cross-head  and  piston- 
rod  may  be  had.  From  the  front  of  the  guiding-cylinder  to  the 
point  where  it  meets  the  base,  the  frame  is  made  in  the  form  of 
an  inclined  concavo-convex  trough  of  sufficient  depth  to  permit 
the  free  movement  of  the  connecting-rod.  The  trough  has  the 
upper  edge  of  one  side  continued  in  a  plane  coinciding  with  the 
centre  of  the  cylinder,  from  the  latter  to  the  enlargement  formed 
to  receive  the  bearing  of  the  crank-shaft.  The  opposite  side  of 
the  trough  extends  from  the  guiding-cylinder,  with  a  gradually 
descending  curve,  to  the  base,  into  the  upper  portion  of  which  it 
gracefully  merges. 

The  steam-cyh'nder  rests  on  a  separate  bed  or  foot,  which  sus- 
tains all  the  bearings  for  the  valve-gear,  and  which  is  placed  on 
a  level  with  the  pillow-blocks  and  main  bed-plate,  to  which  it  is 
securely  bolted  and  dowelled.  There  are  four  valves,  two  steam 
and  two  exhaust,  which  are  of  the  gridiron  or  multiport-slide 
pattern.  They  work  vertically  in  chests  cast  upon  the  cylinder, 
the  two  upon  the  front  being  for  the  induction  cut-off  and  expan- 
sion, and  those  on  the  back  for  the  eduction  or  exhaust.  The 
motion  for  the  steam-  and  exhaust-valves  is  derived  from  a  single 
eccentric,  which  is  so  arranged  as  to  give  a  quick  movement  to  the 
valves  in  opening,  and  a  slow  movement  when  lapping.  The 
stems  of  the  steam-valves  are  connected  with  yokes  having  at 
their  lower  ends  dash-pots,  which  act  as  guides.  These  yokes  are 
operated  by  steel  slides  protruding  through  the  ends  of  hollow 
rocker-arms,  and  acting  upon  the  swinging  toes  held  in  the  yokes. 


THE   engineer's  HANDY-BOOK. 


39 


The  slides  have  a  diagonal  slot,  iu  which  works  a  feather  on  a  rod, 
which  has  a  longitudinal  movement  through  the  hollow  rocker- 
arms  with  which  the  governor  is  connected.  By  this  longitudinal 
motion  through  the  diagonal  feather  and  slot  the  slide  is  auto- 
matically set,  to  engage  the  swinging  toes,  more  or  less,  according 
to  requirements,  to  give  the  valve  its  proper  lift,  and  release  it  on 
the  chord  of  an  arc. 

The  governor  is  of  a  kind  peculiarly  adapted  to  these  engines, 
as  it  is  very  powerful  and  sensitive.  It  rests  on  a  bracket,  or 
shelf,  cast  on  the  side  of  the  bed-plate ;  the  rod  being  connected 
with  a  lever  which  is  fastened  to  the  governor-shaft.  This  sliaft 
carries  two  forked  arms,  which  take  hold  of  the  small  rods  run- 
ning through  the  hollow  rocker-shafts.  These  rods  are  enlarged 
at  their  ends,  where  they  carry  the  adjustable  slides  which  operate 
the  steam-valve  yokes. 

These  engines  are  made  of  the  best  material,  and  fitted  and 
finished  in  the  most  thorough  and  workmanlike  manner.  The 
pistons  are  fitted  with  self-adjusting  steam  packing-rings,  the 
lower  half  of  piston  body,  between  the  packing-rings,  being  fitted 
with  a  brass  shoe,  which  carries  the  weight  of  the  piston,  and  can 
be  so  accurately  adjusted  that  the  piston  must  move  central  with 
the  bore  of  the  cylinder.  The  piston-rods,  wrist-  and  crank-pins, 
and  valve-rod  are  made  of  steel,  and  the  boxes  of  the  best  machine 
brass.  The  connecting-rods  and  crank-shafts  are  made  of  the  best 
hammered  iron,  and  the  pillow-blocks  are  lined  with  anti-friction 
metal.  All  the  rubbing,  revolving,  and  vibrating  surfaces  are 
of  ample  proportions,  and  fitted  with  great  accuracy  and  preci- 
sion. 

The  Wright  Engine  has  undergone  more  changes  in  design  and 
general  appearance,  since  it  was  first  introduced  to  steam  users, 
than  any  other  engine  in  the  country.  The  manufacturer  seems 
to  be  under  the  impression  that,  however  much  he  might  alter, 
he  always  discovers  new  defects  in  his  engine,  and  he  appears  to 
be  governed  more  by  complication  and  weight  than  by  symmetry 
and  convenience.    Consequently,  the  Wright  engines  are  heavy, 


40 


THE   engineer's  HANDY-BOOK. 


unsymmetrical,  and  expensive,  and  perhaps  less  economical  thait 
most  other  automatic  cut-off  engines. 

Examination  of  Candidates. 

The  best  aids  to  a  candidate  applying  for  an  engineer's  cer- 
tificate are  preparation,  coolness,  and  self-possession.  He  must 
be  prepared  to  answer  all  questions  propounded  to  him  promptly 
and  without  hesitation,  thereby  showing  that  he  is  master  of  the 
situation,  as  hesitation  in  answering  questions  will  convey  the 
idea  that  his  knowledge  of  the  subject  to  which  they  relate  is 
linMted.  Hesitation  will,  in  all  probability,  induce  the  examiners 
to  make-  the  examination  more  lengthy  and  rigid  ;  and  it  fre- 
quently happens  that  examinations,  that  might  be  completed  in 
an  hour,  occupy  several  hours,  and  in  some  instances  several  days. 
Consequently,  a  candidate  must  be  prepared  to  demonstrate  prob- 
lems, on  any  subject  embraced  in  the  programme  of  examination, 
by  formulae  of  his  own ;  even  if  formulae  and  problems  be  given 
him,  he  must  be  prepared  to  demonstrate  that  his  method  is 
equally  as  correct,  besides  being  more  brief  and  simple.  He 
must  understand  that  no  amount  of  assurance  will  supply  the 
place  of  study,  nor  will  an  empty  assumption  of  knowledge  com- 
pensate for  a  defective  preparation. 

Necessary  Qualifications  of  Candidates  Applying  for  Ap- 
pointments as  Cadet  Engineers  in  the  U.  S.  Navy. 

Application  may  be  made  by  candidates,  or  their  friends,  to  the 
Secretary  of  the  Navy,  stating  age,  date  of  birth,  educational  ad- 
vantages, and  satisfactory  evidence  of  health  and  good  moral 
character,  which  is  placed  on  register ;  but  neither  the  registering 
of  names,  nor  priority  of  application,  gives  any  assurance  of  ap- 
pointment. The  number  of  appointments  is  limited  by  law  to 
twenty-five  annually.  Applicants  must  be  not  under  sixteen  or 
over  twenty  years  of  age,  and  not  less  than  five  feet  high.  Those 
whose  applications  have  been  favorably  received  will  be  notified 


THE   ENGINEER\s  HANDY-BOOK. 


41 


to  appear  for  examination  on  the  5th  of  Septernl)er,  at  the  Naval 
Academy. 

Candidates  must  be  physically  sound,  well  formed,  and  of 
robust  constitution  ;  and  those  who  possess  the  greatest  skill  and 
experience  in  the  practical  knowledge  of  machinery  (other  quali 
fications  being  equal),  shall  have  precedence  for  admission. 

The  board  of  examiners  have  the  power  of  exercising  discre- 
tion in  the  application  of  the  above  requirements  to  each  indi- 
vidual case,  rejecting  no  candidate  who  is  likely  to  be  efficient  in 
the  service  and  admitting  no  one  who  is  likely  to  prove  physically 
inefficient.  Candidates  once  rejected  by  the  board  of  examination 
are  not  allowed  a  re-examination. 

Candidates  will  be  rejected  for  any  of  the  following  causes: 
Feeble  constitution  ;  greatly  retarded  development ;  permanently 
impaired  general  health.  All  chronic  diseases,  viz. :  Weak  or 
disordered  intellect ;  cutaneous  and  communicable  disease  ;  un- 
natural curvature  of  spine,  torticollis,  or  other  deformity  ;  perma- 
nent inefficiency  of  either  of  the  extremities,  or  articulations  from 
any  cause ;  epilepsy ;  impaired  vision,  or  chronic  disease  of  the 
organs  of  vision ;  hardness  of  hearing,  or  chronic  disease  of  the 
ears ;  chronic  nasal  catarrh,  ozsema,  polypi,  or  enlargement  of 
the  tonsils ;  impediment  of  speech  ;  indications  of  pulmonary  dis- 
ease ;  chronic  cardiac  affections ;  hernia ;  sarcocele ;  hydrocele ; 
stricture ;  fistula,  or  haemorrhoids ;  varicose  veins  of  lower  limbs, 
scrotum,  or  cord ;  chronic  ulcers. 

Every  cadet,  immediately  after  his  admission,  must  supply  him- 
self with  clothing,  bedding,  toilet  articles,  sanitary  utensils,  etc.; 
the  cost  of  which  is  $120.  He  must  also  deposit  $50  with  the 
paymaster,  to  be  expended  in  the  purchase  of  books,  etc. ;  for 
which  he  will  b^ credited  on  the  books.  He  \xill  also,  one  mouth 
after  his  admission,  be  credited  with  the  amount  of  his  expenses 
in  travelling  from  his  home  to  the  Academy ;  but  if  he  resigns 
his  appointment  within  one  year  after  admission,  he  will  be  re- 
quired to  refund  the  amount  advanced  him  for  travelling  ex- 
penses. 

4* 


42  THE  engineer's  handy-book. 

Examination  in  Grafnmar, 

Give  the  possessive  singular  and  the  objective  plural  of  mayor, 
journey,  sky,  she,  strife,  wife. 

Answer. — Possessive  singular:  Mayor's,  journey's,  sky's,  her 
or  hers,  strife's,  wife's.  Objective  plural:  Mayors,  journeys,  skies, 
them,  strifes,  wives. 


Give  the  principal  parts  of  smite,  shed,  lay,  lie,  drown. 


Present. 

Imperfect. 

Present  Participle. 

Past  Participli 

Smite, 

smote, 

smiting. 

smitten. 

Shed; 

shed, 

shedding. 

shed. 

Lay, 

laid. 

laying. 

laid. 

Lie, 

lay. 

lain. 

Drown, 

drowned. 

drowning. 

drowned. 

Lie, 

lied. 

lied. 

Compare  many,  cleanly,  shy,  little,  elder,  without  using  adverbs. 
Answer. — Many,  more,  most ;  cleanly,  cleanlier,  cleanliest ;  shy, 
shyer,  shyest ;  little,  less,  least ;  old,  older,  oldest,  or  old,  elder,  eldest. 

Name  the  moods,  and  explain  the  use  of  each. 

Answer. — Infinitive  expresses  being,  action,  or  passion,  in  an' 
unlimited  manner,  without  person  or  number. 

Indicative  simply  indicates  or  declares  a  thing. 

Potential  expresses  power,  liberty,  or  necessity  of  being,  ac- 
tion, or  passion. 

Subjunctive  represents  being,  action,  or  passion  as  doubtful 
or  contingent. 

Imperative  is  used  in  commanding,  exhorting,  entreating,  or 
permitting.  « 

If  you  blow  your  neighbor's  fire,  don't  complain  if  the  sparks 
fly  in  your  face."    Parse  the  words  in  dark  type. 

Answer. —  If  is  a  conjunction,  connecting  the  sentence,  "don't 
complain  if  the  sparks  fly  in  your  face"  with  "you  blow  your 
neighbor's  fire." 


THE   ENGINEER  \S  HANDY-BOOK. 


43 


Blow  is  an  irregular,  active,  transitive  verb,  subjunctive  mood, 
present  tense,  second  person,  singular,  to  agree  with  its  subject, 
"  your 

Neighbor's  is  a  common  noun,  third  person,  singular  number, 
common  gender,  possessive  case,  governed  by  "  fire." 

Don't  complain  —  contraction  for  "Do  not  complain"  —  is  a 
regular,  active,  intransitive  verb,  emphatic  form,  in  the  imperative 
mood,  second  person,  singular,  to  agree  with  its  subject,  "  you/' 
understood,  conjugated  negatively. 

Youp. — Your  is  a  personal  pronoun,  second  person,  singular, 
common  gender,  to  agree  with  its  antecedent,  "  you,"  possessive 
case,  governed  by  "  face." 

Fire  is  a  common  noun,  third  person,  singular  number,  neuter 
gender,  and  objective  case,  object  of  the  verb  "  blow." 


Spelling. 


Commissary. 

Treasury. 

Debtor. 

Counterfeit. 

Alliance. 

Apparition. 


Identify. 

Precedent. 

Asylum. 

Levy. 

Perpetrate. 

Although. 


Anchorage. 

Correspond. 

Similar. 

Eccentric. 

Susceptible. 

Sufficient. 


Adjacent. 

Occupant. 

Weaken. 

Commercial. 

Insensible. 

Concession. 


Examination  in  Arithmetic. 
Express  16  days,  12  hours,  47  minutes,  25  seconds  as  a  fraction 
of  23  days,  3  hours,  30  minutes,  23  seconds,  (lowest  terms.) 

d.     hrs.    min.  sec. 

Answer.    23    3    30    23  =  1,999,823  seconds. 

d.     hrs.  min.  sec. 

16    12   47    25  =  1,428,445  " 

1428445 

1999823 

Give  the  rule  for  finding  the  cube  root  of  any  number,  and  illus- 
trate by  an  example. 

Answer. — First.  Point  off  from  right  to  left,  if  au  iuteger  or 


44  THE   ENGINEER'S  HANBY-BOOK. 

whole  number,  and  from  left  to  right,  if  a  decimal,  in  orders  or 
places  of  three.  Second,  Ascertain  the  highest,  root  of  the  first 
order,  and  place  it  tQ  the  right  of  the  number,  as  in  long  division. 
Third.  Cube  the  root  thus  found,  and  subtract  it  from  the  first 
order,  and  to  the  remainder  annex  the  next  order ;  then  square 
the  root  already  found,  and  multiply  it  by  three,  with  two  ciphers 
annexed,  for  a  trial  divisor ;  next  find  how  often  this  divisor  is 
contained  in  the  dividend,  and  write  the  result  in  the  root. 
Last:  Add  together  the  trial  divisor,  three  times  the  product  of 
the  first  figure  of  the  root,  by  the  second,  with  one  cipher  annexed, 
and  the  square  of  the  second  figure  in  the  root ;  multiply  this  last 
sum  by  the  last  figure  in  the  root,  and  subtract  as  above ;  to  the 
remainder  annex  the  next  order,  and  proceed,  as  before  directed, 
until  all  the  orders  are  worked. 


To  find  the  4/493039. 

493039(79 


7x7 

X  7  = 

343 

7  X 

7x3  = 

14700 

150039 

7  X 

9x3  = 

1890 

9x9  = 

81 

16671 

150039 

To  find  the  V  403583-419. 

403583-419(73-9 


7 

X 

7x7  = 

343 

7  X 

7 

X 

3 

=  14700 

60583 

7  X 

3 

X 

8 

=  630 

3 

X 

3 

=  9 

15339 

46017 

73  X  73 

X 

3 

1598700 

14566419 

73  X  3 

X 

3 

19710 

9 

X 

9 

81 

1618491 

14566419 

THE    engineer's  TrANDY-BOOK. 


45 


The  cube  of  any  number  is  that  number  multiplied  by  itself 
three  times. 

Give  the  rule  for  findim/  the  square  root  of  any  number ,  and 
illustrate  by  an  example. 

Answer. — First,  Point  off  from  right  to  left,  if  an  integer  or 
whole  number,  and  from  left  to  right,  if  a  decimal,  in  orders  or 
places  of  twos.  Second.  Ascertain  the  highest  root  in  the  first 
order,  and  place  it  at  the  right  of  the  number,  as  in  long  division. 
Third.  Square  this  root,  and  subtract  it  from  the  first  order;  to 
the  remainder  annex  the  next  order,  and  double  the  root  already 
found,  and  place  it  to  the  left  of  this  dividend.  Fourth.  Ascer- 
tain how  often  this  divisor  is  contained  in  all  but  the  final  figure 
of  the  dividend,  and  place  the  quotient  to  the  right  of  the  root 
already  obtained,  and  to  the  right  of  the  trial  divisor.  Fifth.  Mul- 
tiply this  divisor  by  the  final  figure  in  the  root,  and  subtract  as 
before ;  if  the  remainder  after  a  division  m  negative,  take  a  figure 
for  the  last  figure  in  the  root  one  less  than  before,  and  proceed  as 
directed  in  Fourth  and  Fifth.  In  like  manner  proceed  until  all 
the  orders  have  been  worked. 

To  find  the  |/  590^49. 

5,90-49(24-3 
4 

44)  190 
176 
483)  1449 
1449 

To  find  the  |/-075625. 

07,56,25(-275 
4 

47)  356 
329 
545)  2725 
2725 

Any  number  multiplied  by  itself  is  squared. 


46 


THE   engineer's  HANDY-BOOK. 


Define  the  terms  logarithms  and  hyperbolic  logarithms,  and 
explain  their  use. 

Answer. — The  logarithm  of  a  number  is  the  exponent  of  the 
power  to  which  it  is  necessary  to  raise  a  fixed  number  in  order  to 
produce  the  first  number.  The  use  of  logarithms  is  to  abridge 
numerical  computations.  The  operations  of  multiplication,  divi- 
sion, involution,  and  evolution  are  very  much  abridged  by  their 
use.  Any  power  of  a  given  number  may  be  found  by  logarithms 
as  follows:  The  logarithm  of  any  power  of  a  given  number  is 
equal  to  the  logarithm  of  the  number  multiplied  by  the  exponent 
of  the  power. 

Example. — To  find  the  fifth  power  of  9,  logarithm  9  =  0*954243 
X  5  =  4*771215,  and  the  number  corresponding  to  this  is  59049. 
Conversely.  Any  root  of  any  number  may  be  found  by  logarithms 
as  follows :  The  logarithm  of  the  root  of  a  given  number  is  equal 
to  the  logarithm  of  the  number  divided  by  the  index  of  the  root. 

Example. — To  find  the  cube  root  of  4096,  logarithm  4096  = 
3*612360  ^  3  =  1*204120,  and  the  number  corresponding  to  this 
logarithm  is  16. 

Hyperbolic  logarithms  is  a  system  of  logarithms,  so  called, 
because  the  numbers  express  the  areas  between  the  asymptote  and 
curve  of  the  hyperbola.  The  hyperbolic  logarithm  of  any  number 
is  the  common  logarithm  of  the  same  number  in  the  ratio  of 
2*30258509  to  1,  or  as  1  to  -43429448. 

Explain  the  terms  geometry  and  trigonometry. 

Answer. — Geometry  is  the  science  of  position  and  extension ; . 
that  branch  of  mathematics  which  has  for  its  object  the  investiga- 
tion of  the  relations,  properties,  and  measurement  of  solids,  sur- 
faces, lines,  and  angles.  Trigonometry  is  that  branch  of  mathe- 
matics whose  object  it  is  to  determine  unknown  angles,  or  sides 
of  triangles,  by  means  of  others  which  are  known ;  the  art  or 
science  of  measuring  triangles.  It  also  treats  of  the  general  rela- 
tions existing  between  the  trigonometrical  functions  of  angles  or 
arcs. 


THE   ENCJINEEr\s    IF  A  N     Y  -  JU)  O  K  . 


47 


Give  the  meaniyujs  of  the  tenns  quotient^  product^  and  prohlern. 

Answer. — A  quotient  is' the  result  of  au  operation  in  division ; 
Si  product  is  the  result  of  an  operation  in  multiplication  ;  a  problem 
is  a  question  requiring  some  unknown  truth  to  be  demonstrated. 

Oive  the  meanings  of  the  terms  axiom,  theorem,  proposition,  corol- 
lary, and  solution. 

Answer. — An  axiom  is  a  self-evident  truth  ;  a  theorem  is  a  state- 
ment of  a  truth  or  principle  which  is  to  be  demonstrated  ;  a  prop- 
osition  is  a  term  applied  to  a  theorem  or  a  problem ;  a  corollary  is 
an  obvious  consequence  deduced  from  one  or  more  propositions  ; 
a  solution  is  the  result  arising  from  any  mathematical  proposition 
or  calculation. 

Give  the  names  of  the  various  triangles,  their  peculiarities,  etc. 

Answer. — A  triangle  is  a  figure  having  three  sides  and  three 
angles  ;  an  isosceles  triangle  has  two  sides  and  the  angles  at  the  base 
equal ;  a  scalene  triangle  has  no  two  sides  or  angles  equal ;  an  obtuse- 
angled  triangle  has  one  obtuse  angle  in  it ;  a  right-angled  triangle 
has  one  right  angle  in  it ;  an  equilateral  triangle  has  all  three  sides 
and  angles  equal ;  an  acute-angled  triangle  has  one  acute  angle  in  it. 

Examination  in  Geography. 

Name  the  States  which  have  any  coast-line  on  the  great  lakes, 
between  the  United  States  and  Canada,  telling  in  each  ease  what 
lake  the  State  touches. 


Answer. 

New  York, 

Lakes  Ontario  and  Erie. 

Pennsylvania, 

Lake  Erie. 

Ohio, 

Lake  Erie. 

Michigan, 

Lakes  Erie,  St.  Clair,  Huron,  Michigan,  and 

Superior. 

Indiana, 

Lake  Michigan. 

Illinois, 

Lake  Michigan. 

Wisconsin, 

Lakes  Michigan  and  Superior. 

Minnesota, 

Lake  Superior. 

48 


THE   ENGINEER'S  HANDY-BOOK. 


Where  and  on  what  waters  are  Buenos  Ayres,  Bordeaux,  Bel- 
grade, Jackson,  Bombay  ?  Tell  which  of  the  above  are  capitals  of 
States,  and  of  what  States  they  are  capitals. 

Answer. — Buenos  Ayres  is  on  the  Rio  de  la  Plata,  and  is  the 
capital  of  the  Argentine  Confederation,  South  America;  Bor- 
deaux is  on  the  Garonne,  in  France ;  Belgrade  is  on  the  Danube, 
in  "  Turkey  in  Europe ; "  Jackson  is  on  the  Pearl  River,  and  is 
the  capital  of  Mississippi ;  Bombay  is  in  Hindostan,  Asia,  on  the 
coast  of  the  Arabian  Sea. 

Define  the  source,  direction,  and  mouth  of  the  Ganges  River, 
Clyde  River,  Pruth  River,  Santee  River. 

Answer. — The  source  of  the  river  Ganges  is  in  the  Hima- 
laya Mountains ;  its  direction  is  south-east ;  its  mouth  is  in  the 
north-eastern  part  of  Hindostan,  and  empties  into  the  Bay  of  Ben- 
gal. The  source  of  the  Clyde  is  in  the  Lammermoor  Hills,  Scot- 
land ;  flows  in  a  north-westerly  direction,  and  discharges  into  the 
Firth  of  Clyde.  The  source  of  the  Pruth  is  in  the  eastern  base 
of  the  Carpathian  Mountains,  in  Austria  ;  flows  first  east,  then 
south-east,  and  finally  south,  emptying  into  the  Danube.  The 
Santee  is  formed  by  the  junction  of  the  Congaree  and  Wateree 
Rivers  in  the  central  part  of  South  Carolina ;  flows  south-east,  and 
empties  into  the  Atlantic  Ocean. 

Where  is  Mount  Snowden,  the  Atlas  Mountains,  the  Elburz 
Mountains,  Mount  -^tna.  Mount  Chimborazo  ? 

Answer. — Mount  Snowden  is  a  peak  in  the  Cambrian  range  of 
Mountains,  in  Wales.  The  Atlas  Mountains  are  in  the  "  Barbary 
States,"  in  Northern  Africa.  The  Elburz  Mountains  are  in 
Northern  Persia,  and  form  part  of  the  great  Himalayan  range. 
Mount  Chimborazo  is  a  volcano  in  the  Andes  range,  in  Ecuador, 
South  America. 

Name  five  islands  of  the  Mediterranean,  define  their  position, 
and  state  to  what  Power  each  belongs. 

Answer.  —  The  Balearic  group,  off*  the  east  coast  of  Spain,  be- 
longs to  Spain.    Corsica,  off*  the  west  coast  of  Italy,  belongs  to 


THE   ENGINEER'S    11  A  N  D  Y  -  B  ()  O  K  . 


49 


France,  Sardinia,  off  the  west  coast  of  Italy,  belongs  to  Italy. 
Sicily,  off  the  south-west  coast  of  Italy,  belongs  to  Italy.  Candia, 
or  Crete,  off  the  south  coast  of  Greece,  belongs  to  Turkey. 

Exmnination  in  Natural  Philosophy* 

Define  centre  of  gravity  of  a  body.  How  can  the  position  of 
the  centre  of  gravity  of  an  irregular  body  be  determined  ? 

Answer. — The  centre  of  gravity  of  a  body  is  the  point  through 
which  the  resultant  of  the  weights  of  the  several  component  par- 
ticles of  a  body  always  passes.  The  centre  of  gravity  of  an  ir- 
regular body  may  be  determined,  experimentally,  by  suspend- 
ing it  successively  from  any  two  points,  and,  after  it  has  come 
to  a  state  of  rest,  or  is  in  equilibrium,  drawing,  by  means  of  a 
plumb-line,  the  verticals  through  the  points  of  suspension.  The 
intersection  of  these  lines  will  be  the  centre  of  gravity  of  the 
body. 

If  the  specific  gravity  of  iron  is  7  8  and  that  of  gold  19*4,  find 
the  weight,  in  water,  of  a  substance  composed  of  one  pound  of  iron 
and  one  pound  of  gold. 

Answer. —  In  this  problem,  first  find  the  solid  contents,  in  inches, 
of  one  pound  respectively  of  iron  and  of  gold,  and  add  them. 
Then,  if  one  cubic  foot  of  water  weighs  62*5  lbs.,  one  cubic  inch 
will  weigh  '036.  Then  multiply  the  combined  solid  contents  in 
inches,  of  one  pound  of  iron  and  gold,  by  the  solid  content  in 
inches  of  ©ne  cubic  inch  of  water.    Thus : 

1  lb.  of  iron  =  3*54  cubic  in.  of  solid  contents. 
1  "   "  gold  =  1-42       "       "  " 

4"96  cubic  in.  of  solid  contents  of  both. 

Then  4-96  X -036  =  -17856. 
This  product  deducted  from  2  lbs.  will  be 

2-00000 
0^7856 
1-82144 
5  D 


50 


THE   ENGINEER'S  HANDY-BOOK. 


Then  multiply  the  weight  of  1  cu.  ft.  of  water  respectively  by 
that  of  iron  and  gold,  and  dividing  by  1728  we  get 

62-5  X  7-8=  457-5 -1728-=  3-54  cu.  in. 
62-5  X 19-4  ==1212-5    1728  =  1-42  "  " 

4-96  "  " 

A  cask  weighing  236  lbs.  4  oz.  floats  in  a  square  cistern  of 
water  whose  side  is  2  ft.  6  in.  On  the  removal  of  the  cask,  find 
how  much  the  water  will  sink  in  the  cistern,  supposing  a  cubic 
foot  of  water  to  weigh  63  lbs.  ? 

Answer. — The  weight  of  cask  is  236  lbs.  4  oz.,  or,  (if  expressed 
decimally,)  236*25  lbs.  Side  of  cistern  is  2  ft.  6.  in.,  or  30  inches ; 
this  squared  equals  900  inches.  Then  the  weight  of  1  cubic 
foot  of  water  is  to  1  cubic  foot  of  water  as  weight  of  cask  is  to 
cubic  feet  of  water  displaced  by  the  cask. 

lbs.  oz,  ft.  in.     ft.  in. 

236  4  =  236-25  — cistern  2  6  x  2  6  =  900  cu.in. 

lbs.  cu.ft.        lbs.  cu,  in. 

As  63  :  1  :  :  236*25  :  3*75  cu.  ft.    3-75  x  1728  =  6450 
and  6450     900  =  7*2  in. 

How  high  will  a  common  pump  raise  oil  having  a  specific 
gravity  of  0*88,  if  it  raise  water  33  feet?  How  would  this  height 
be  affected  if  the  force  of  gravity  was  doubled  ? 

Answer.  — The  specific  gravity  of  water  is  expressed  by  unity. 
Then  the  specific  gravity  of  oil  is  to  the  specific  gravity  of  water 
as  the  height  to  which  water  is  raised  is  to  the  height  ta  which  oil 
will  be  raised  by  the  same  pump. 

•88  :  1  : :  33  :  37*5  ft. 

How  far  would  a  solid  of  any  material  sink  into  a  fluid  denser 
than  itself? 

Answer. — On  the  principle  that  fluids  become  denser  the 
deeper  they  go,  a  'solid  would  sink  in  any  fluid  till  it  displaced 
a  volume  of  it  equal  to  its  own  density. 

Suppose  the  specific  gravity  of  mercury  be  14  and  that  of  iron 
7.    How  far  would  a  cubic  foot  of  iron  sink  into  the  mercury? 


THE   engineer's  HANDY-BOOK. 


51 


Answer. — One-half  of  its  volume,  or,  if  in  a  normal  position, 
one-half  its  depth. 

A  cube  of  cork,  whose  edge  is  1  foot,  floating  vertically  in  water, 
sinks  to  the  depth  of  2'88  inches.    Find  its  specific  gravity. 

Answer.  — First  find  the  cubic  contents  of  the  water  displaced, 
by  multiplying  the  depth  to  which  the  cork  sunk  by  the  length 
and  breadth  of  the  same.  Thus,  2*88  X  12  ==^414*72  cu.in.;  then, 
if  1728  cu.  in.  =  62-5  lbs.,  414-72  cu.  in.  =  15  lbs.  Hence,  as 
62-5  :  1000  : :  15  :  240,  specific  gravity  of  cork. 

Give  the  readings  of  Fahrenheit's  thermometer  which  cor- 
respond to  110°,  10°,  29°  Centigrade;  also  the  readings  of  the 
Centigrade  thermometer  which  correspond  to  77°  and  23°  Fah- 
renheit. At  what  temperature  Centigrade  will  these  two  ther- 
mometers  have  the  same  readings  ? 

Answer. — To  change  Centigrade  degrees  to  Fahrenheit  degrees, 
multiply  the  Centigrade  degrees  by  9  and  divide  by  5,  and  to  the 
quotient  add  32.    The  result  is  Fahrenheit  degrees. 


a 

a 

C. 

110° 

10° 

29° 

9 

9 

9 

5)  990 

5)  90 

5)  261 

198 

18 

52-2 

32° 

32° 

32° 

230°  F. 

50°  F. 

84-2°  F. 

To  change  Fahrenheit  degrees  to  Centigrade  degrees,  deduct 
32°  from  Fahrenheit  degrees ;  then  multiply  by  5  and  divide  by 
9. .  The  result  is  Centigrade  degrees. 

Explain  the  meaning  of  the  term  Conic  Section. 

Answer. — A  conic  section  is  a  curve  cut  out  of  the  surface  of 
a  right  cone  having  a  circular  base,  by  a  plane.  The  sections  re- 
sulting from  the  cutting  of  a  cone,  are  the  triangle,  the  circle,  the 
ellipse,  the  parabola,  and  the  hyperbola ;  though  the  term  conic 
section  is  confined  to  the  last  three. 


54  THE   ENGINEER'S  HANDY-BOOK. 


Woodbury,  Booth  &  Pryor's  Automatic  Cut-Off  Engine. 

The  cuts  on  pages  52  and  53  represent  Woodbury,  Booth  & 
Pryor's  Automatic  Cut-off  Engine.  It  will  be  observed  that  it  is 
built  upon  what  is  known  as  the  girder  or  truss  frame,  a  design 
which  has  been  received  with  more  favor,  and  more  universally 
adopted  by  intelligent  engineers,  both  in  this  country  and  Europe, 
than  any  other.  In  fact,  it  is  fast  superseding  all  previous  forms 
of  bed-plates.  This  perhaps  arises  from  the  fact  that  it  is  the 
best  disposition  that  can  be  made  of  a  certain  quantity  of  mate- 
rial, to  insure  strength  and  rigidity  without  extra  weight,  as  the 
centre  line  of  the  frame  coincides  with  the  plane  of  the  line  of  the 
strains  and  with  the  centre  line  of  the  engine.  It  is  faced  at 
one  end  to  receive  the  false  head  between  the  frame  and  cylinder, 
the  piston-rod  stufSng-box  being  cast  with  the  head.  The  cylinder 
rests  on  a  handsomely  designed  pedestal,  the  other  end  of  the 
frame  containing  the  back  leg  and  main  pillow-block  bearing. 

Valve-Gear. — The  main  valve  is  an  ordinary  D  slide-valve,  an 
arrangement  which,  since  the  advent  of  the  steam-engine,  in  con- 
sequence of  its  simplicity  of  design,  positiveness  of  action,  moderate 
first  cost,  non-liability  to  become  deranged  and  get  out  of  order; 
that  it  performs  the  double  function  of  admission  and  release,  as 
well  as  from  the  ease  and  convenience  with  which  it  can  be  re- 
paired or  removed,  has  held  its  own  against  all  new  innovations  in 
steam-valves  and  valve-gear.  Fig.  1  shows  a  horizontal  section 
through  its  centre,  and,  as  will  be  observed,  it  is  driveu  by  an 
eccentric  on  the  main  shaft  through  the  intervention  of  a  rocker- 
arm.  The  cut-off  valve,  a  section  of  which  may  be  seen  in  Fig. 
2,  is  cylindrical  in  form,  and  works  in  a  small  cylinder  attached 
to  the  back  of  the  main  valve,  which  is  cast  in  one  piece  with  it. 
In  consequence  of  the  arrangement  of  the  ports,  it  is  perfectly  bal- 
anced ;  and,  owing  to  its  having  diagonal  admission  edges,  with 
ports  to  correspond,  by  rolling  it  slightly  in  its  seat  it  will  cut  off 
at  any  point  between  zero  and  three-quarter  stroke,  according  to 
requirements. 


THE   ENGINEER'S  HANDY-HOOK. 


55 


The  cut-off  eccentric  rod  connects  with  the  slide  working  in 
the  bracket  by  means  of  a  ball-and-socket  joint,  which  allows  the 
valve  to  rotate  in  its  seat,  more  or  less,  according  to  the  require- 
ments of  the  load  and  pressure.  The  rotation,  which  never  exceeds 
one-quarter  of  a  revolution  of  the  valve,  is  accomplished  by  a  seg- 


Fig.  2. 

ment  on  the  cut-off  valve-slide,  working  into  a  rack  attached  to 
the  governor  spindle.  The  slide  is  a  round  steel  rod,  having  a 
number  of  grooves  milled  in  it  lengthwise,  sliding  through  corre- 
sponding tongues  in  the  segment.  This  arrangement  places  the 
cut-off  at  all  times  under  complete  control  of  the  governor,  and, 
as  the  rolling  movement  of  the  cut-off  is  combined  with  the  sliding 


56 


THE   engineer's  HANDY-BOOK. 


of  the  valve  in  its  seat,  it  offers  but  very  slight  resistance,  and 
induces  less  friction,  even,  than  that  of  an  ordinary  throttling- 
valve.  These  cut-offs  embody  the  following  advantages:  Sim- 
plicity of  construction,  positiveness  of  action,  an  entire  absence  of 
releasing  gear,  non-liability  of  derangement,  freedom  from  violent 
shocks,  accuracy  in  cutting  off,  and  uniformity  of  speed. 

The  Governor. — The  governor  is  of  peculiar  design ;  the  arms 
extend  across  the  centre,  and  have  their  point  of  suspension  on  the 
opposite  side  of  the  ball,  which  insures  great  sensitiveness,  as  they 
have  a  very  extensive  range  of  movement  with  a  slight  variation 
of  speed.  Besides,  the  governor  has  comparatively  no  w^ork  to 
perform,  as  the  rolling  of  the  balance  cut-off  while  sliding  length- 
wise in  its  seat  requires  but  a  very  small  amount  of  force.  In 
fact,  the  governor  has  nothing  to  do  but  to  regulate  the  speed, 
without  being  hampered  by  the  movement  of  cut-off  valves,  that 
have  large  rubbing  surfaces  exposed  to  boiler  pressure. 

The  arrangement  for  the  admission  and  release  of  the  steam 
to  and  from  the  cylinder  automatically,  embodies  the  right  prin- 
ciple by  w^hich  to  work  steam  expansively  and  economically. 
There  are  numerous  industries  in  Avhich  uniform  speed  is  not  only 
a  desideratum,  but  a  necessity.  It  must  not  be  understood,  how- 
ever, that  all  automatic  cut-offs  and  governors  are  capable  of  pro- 
ducing satisfactory  and  economical  results,  as  many  of  them  in 
use  at  the  present  day  fail  to  meet  these  requirements.  The  gov- 
ernors of  these  engines  are  provided  with  a  dash-pot,  which  acts  as 
a  cushion,  and  obviates  the  jerking  so  common  in  many  governors, 
and  which  is  so  detrimental  to  the  uniform  working  of  an  engine. 

Some  of  the  advantages  of  the  Woodbury,  Booth  &  Pryor 
engines  are,  that  they  are  handsome  in  design,  and  convenient 
and  simple  in  arrangement ;  that  they  are  built  of  the  best  mate- 
rials, fitted  with  the  greatest  care,  and  steel  and  composition  metals 
are  freely  used  on  parts  subjected  to  the  most  wear,  thus  insuring 
durability  as  well  as  reducing  the  cost  of  maintenance  to  a  mini- 
mum ;  that  there  is  secured  the  highest  degree  of  economy  and  the 
closest  approximation  to  uniform  speed  ;  that  the  ports  are  dropped 


THE   ENGINEEr\s  HANDY-JU)0K. 


57 


sufficiently  low  to  drain  the  cylinder,  the  water  of  condenaati(Hi 
being  drawn  from  the  steam-chest  instead  of  being  forced  through 
the  cylinder ;  that  owing  to  the  positive  valve-motion  they  can  be 
run  at  a  high  rotative  speed ;  that  provision  is  made  for  catching 
all  the  drip  oil  and  water;  that  the  crank-pins  have  a  hollow 
cellar  or  receptacle  in  the  centre  for  the  purpose  of  containing  an 
auxiliary  lubricant,  which  will  melt  and  prevent  the  pin  from 
cutting  should  the  oil-cup  be  neglected  or  fail  to  feed ;  and  that 
all  wearing  parts  can  be  easily  and  accurately  adjusted. 

In  fact,  these  engines  seem  to  embody  all  the  good  points  in 
the  best  descriptions  of  engines,  and  many  others  which  are  pecu- 
liar to  thehiselves,  which  render  them  equal,  if  not  superior,  to 
any  other  automatic  cut-off  engines  in  the  market.  They  are 
manufactured  by  Woodbury,  Booth  &  Pryor,  Rochester,  N.  Y. 

Qualifications  of  Candidates  for  the  U.  S.  Revenue  Service. 

First. — Candidates  for  appointments  as  second  assistant  en- 
gineers must  not  be  less  than  twenty-one  nor  more  than  thirty 
years  of  age  ;  they  must  be  of  good  moral  character  and  correct 
habits ;  they  must  have  worked  not  less  than  eighteen  months  in 
a  steam-engine  factory,  or  served  the  same  period  as  an  engineer 
on  board  of  a  steamer  having  a  condensing  engine ;  they  must 
also  produce  favorable  testimonials  from  the  superintendent  of 
the  machine-shop,  or  chief-engineer  of  the  steam-ship,  as  to  their 
ability. 

Second. — They  must  be  able  to  describe  and  sketch  the  dif- 
ferent parts  of  marine  steam-engines  and  boilers,  and  explain 
their  uses  and  mechanical  movements,  the  method  of  putting 
them  in  operation,  regulating  their  action,  and  guarding  against 
danger. 

Third. — They  must  be  fair  arithmeticians  and  have  a  knowl- 
edge of  rudimentary  mechanics,  be  capable  of  writing  a  fair, 
legible  hand,  and  have  some  knowledge  of  chemistry,  particu- 
larly of  combustion  and  corrosion. 

Fourth. — Candidates  who  excel  in  practical  experience  and 


58 


THE   ENGINEER'S  HANDY-BOOK. 


professional  skill  will  be  given  the  preference,  both  in  admission 
and  promotion. 

Fifth.  —  Any  candidate  producing  a  false  certificate  of  age,  time 
of  service,  or  character,  or  making  a  false  statement  to  the  board 
of  examiners,  will  be  dropped  from  the  list. 

Standard  of  Examination  for  Assistant  Engineer  in  the 
U.  S.  Revenue-Cutter  Service. 

First  Assistant  Engineer. 

First. —  They  must  pass  before  the  board  of  examiners  a 

thorough  examination  upon  the  subjects  prescribed  for  second 
assistant  engineers,  and  be  able  to  explain  the  principles,  peculi- 
arities, functions,  and  uses  of  the  different  kinds  of  valves  and 
valve-gear,  as  applied  to  marine  steam  machinery. 

Second.  —  They  must  understand  the  construction,  principles, 
peculiarities,  and  uses  of  the  various  mechanical  arrangements  em- 
ployed in  working  steam  expansively. 

Third. — They  must  understand  the  construction  of  the  marine 
boilers  in  most  general  use,  their  attachments,  and  the  functions 
and  uses  of  the  same. 

Fourth. —They  must  be  able  to  explain  the  most  general 
causes  of  derangement  in  the  operation  of  air-  and  feed-pumps 
and  pipes,  and  the  most  practicable  method  of  preventing  and 
remedying  them. 

Fifth. — They  must  have  a  knowledge  of  the  chemical  and 
mechanical  causes  which  induce  the  formation  of  scale  in  steam- 
boilers,  and  the  most  practicable  method  of  preventing  and  re- 
moving the  same. 

Sixth. — They  must  be  acquainted  with  the  general  construc- 
tion, principles,  peculiarities,  and  uses  of  the  different  kinds  of 
surface-condensers  in  present  use. 

Seventh.  —  They  must  be  able  to  calculate  the  loss  induced 
by  blowing  off,  for  the  purpose  of  keeping  the  water  in  the  boilers 
at  a  uniform  degree  of  saturation,  and  understand  the  principles 


THE    engineer's  HANDY-HOOK. 


59 


of  the  various  instruments  employed  to  determine  the  water's 
saturation,  as  well  as  the  method  of  graduating  them. 

Eighth. — They  must  understand  the  principles,  most  practicable 
limits,  and  advantages  of  working  steam  expansively,  and  be  able 
to  calculate  the  same. 

Ninth. — They  must  have  a  knowledge  of  the  construction  of 
the  indicator,  know  how  to  apply  it,  and  intelligently  explain  its 
diagrams. 

Tenth. — They  must  be  acquainted  with  the  construction  and 
the  principles  on  which  the  action  of  steam-  and  vacuum-gauges 
is  based,  and  the  causes  of  their  derangement. 

Eleventh. — They  must  have  experience  in  building,  erecting, 
and  repairing  steam  machinery. 

Examinations  for  the  Mercantile  Marine  Service. 

The  following  are  among  the  questions  most  generally  asked 
by  examiners  of  engineers  who  apply  for  license  in  the  mercan- 
tile marine  service. 

How  long  have  you  served  as  a  fireman? 

How  long  have  you  served  in  the  engine-room  at  sea,  and  in 
what  capacity  ? 

With  what  description  of  engines  have  you  served  at  sea  — 
paddle  or  screw,  jet-condensing,  surface-condensing,  or  non-con- 
densing engines,  compound,  trunk,  inverted  cylinder,  or  hori- 
zontal engines? 

What  size  were  the  engines? 

Explain  the  difference  between  condensing  and  non-condensing 
engines  in  principle  and  in  point  of  economy. 

In  case  the  pump  fails  to  work,  what  course  would  you  adopt? 
and  what  are  the  most  general  causes  of  the  failure  of  lift,  or  suc- 
tion-bilge, or  steam-pumps  failing  to  act  ? 

If  the  pumps  fail  to  work,  the  water  be  low,  and  you  are  in  dan- 
ger of  being  driven  on  a  lee-shore,  what  course  would  you  adopt? 

What  is  the  object  of  braces  in  a  steam-boiler?  Which  are 
preferable,  a  few  large  ones,  or  numerous  small-sized  ones  ? 


60 


THE   ENGINEER'S  HANDY-BOOK. 


What  parts  of  a  marine  engine  are  most  likely  permanently  to 
disable  the  ship  in  case  of  breakage  ? 

Demonstrate  by  example  (taking  your  own  data)  the  safe 
working  and  bursting  pressure  of  a  boiler. 

Demonstrate  by  example  (taking  your  own  data)  the  load 
necessary  to  be  placed  on  the  lever  of  a  safety-valve  for  a  given 
pressure  of  steam. 

With  what  description  of  boilers  have  you  served  at  sea  — 
wet-bottomed,  dry-bottomed,  multi-tubular,  sectional  or  flue,  water- 
or  fire-tube  boilers  ? 

What  engine  defects  have  come  under  your  notice  at  sea? 
What  caused  those  defects?  How  were  they  remedied?  Give 
the  names  of  the  steamers. 

What  boiler  defects  have  come  under  your  notice  at  sea? 
What  caused  those  defects  ? 

How  were  they  remedied  ?    Give  the  names  of  the  steamers. 

Qualifications  of  Stationary  Engineers. 

In  locations  where  the  law  requires  persons  having  charge  of 
stationary  steam-engines  to  procure  certificates  of  competency,  the 
examination  generally  embraces  the  following  subjects : 

First. — Whether  the  candidate  has  charge  of  an  engine  at 
present.  If  not,  where  he  had  charge  of  one  last.  If  he  has  a 
recommendation  from  his  last  employer.  What  was  the  size  of 
the  engine  of  which  he  had  charge,  diameter  of  cylinder,  stroke, 
travel  of  piston,  pressure  as  shown  by  the  steam-gauge,  etc.,  and 
what  power  such  an  engine  was  capable  of  developing. 

Second.  —  Whether  the  engine  was  condensing  or  non-con- 
densing, horizontal,  vertical,  inclined,  oscillating,  trunk,  or  beam, 
and  the  difference  between  a  condensing  and  a  non-condensing 
engine. 

Third. — Whether  the  engine  was  automatic,  cut-off  or  slide, 
throttling-  or  poppet-valve,  and  the  diff'erence  between  an  auto- 
matic cut-off  and  slide-valve  throttling-engine. 

Fourth.  —  What  he  would  consider  his  first  duty  on  entering 


THE   ENGINEER'S  HANDY-BOOK. 


61 


the  engine-room  after  being  absent,  or  on  taking  charge  of  an 
engine  and  boiler  for  the  first  time.  How  he  would  proceed  to 
set  a  slide-valve.  How  he  could  tell,  without  examining  the 
valve,  whether  the  engine  was  exhausting  regularly  or  not,  and 
what  he  would  do  before  starting  an  engine,  if  it  had  been  stand- 
ing still  for  some  time,  particularly  in  cold  weather. 

Fifth. — Whether  the  boilers  he  had  charge  of  were  plain  cylin- 
der, flue,  tubular,  tubulous,  or  fire-box;  whether  they  were  in- 
ternally or  externally  fired  ;  and  whether,  on  any  occasion,  he 
ever  fired  up  under  a  boiler  and  afterwards  discovered  there  was 
insufficient  water  in  it. 

Sixth. — What  advantages  and  disadvantages  do  plain  cylinder, 
flue,  tubular,  tubulous,  and  fire-box  boilers  possess  over  each  other 
in  point  of  economy  of  fuel,  efficiency,  safety,  durability,  and 
space  ? 

Seventh.  —  How  often  should  a  boiler  be  cleaned,  and  how 
should  it  be  managed  before  cleaning?  How  often  ought  boilers 
to  be  examined,  and  what  should  be  the  character  of  such  an  ex- 
amination? What  are  the  object  and  nature  of  the  different  tests 
now  employed,  and  their  effect  on  the  boiler  ? 

Eighth.  —  What  course  he  would  pursue  in  case  the  feed-water 
was  cut  off  for  a  short  time,  or  what  would  he  do  if  cut  off*  for  an 
indefinite  period,  or  from  any  cause  became  dangerously  low; 
how  he  would  proceed  if  obliged  to  stop  his  engiue  when  steam 
was  blowing  off*  at  the  safety-valve  and  a  heavy  fire  in  the  fur- 
nace ;  and  how  he  would  regulate  his  fire,  when  starting  to  raise 
steam,  with  cold  water  in  the  boiler. 

Ninth. — The  difference  in  the  strains  to  which  the  shell,  flues, 
tubes,  crowns,  and  other  parts  of  steam-boilers  are  subjected,  as 
well  as  those  which  the  longitudinal  and  curvilinear  seams  have 
to  bear ;  also  the  difference  in  strength  between  single-  and  double- 
riveted  seams,  the  loss  induced  by  punching  or  drilling  the  holes 
for  the  rivets,  and  the  difference  in  strength  between  punched  and 
drilled  holes,  and  between  hand  and  machine  riveting. 

Tenth.  —  The  diameter  and  length  of  the  boiler  of  which  he 
6 


62 


THE   engineer's  HANDY-BOOK. 


had  charge  last ;  the  diameter  and  length  of  the  tubes  or  flues ; 
the  thickness  of  the  shell ;  the  number  of  square  feet  of  heating 
surface  in  it — also  of  grate  surface;  the  area  of  the  safety-valve, 
and  whether  the  boiler  was  single  or  double  riveted. 

Eleventh. — The  safe  working-  and  bursting-pressure  of  boil- 
ers, single  or  double  riveted,  of  different  diameters  and  of  different 
thicknesses  of  iron ;  the  proportions  of  grate  and  heating  surfaces 
that  would  be  capable  of  generating  sufficient  steam  to  develop  a 
horse-power ;  and  the  orifice  of  safety-valve  that  would  liberate 
that  quantity  of  steam,  provided  that  all  other  means  of  escape 
were  closed. 

Twelfth. — A  demonstration,  from  his  own  data,  of  the  weight 
necessary  to  place  on  the  safety-valve  for  a  given  pressure  when 
the  length  of  the  lever  and  the  area  of  the  safety-valve  are  known  ; 
also  the  pressure  required  to  lift  a  certain  weight,  with  a  given 
length  of  lever  and  area  of  valve. 

Thirteenth. — What  are  the  most  probable  causes  of  lift  or 
suction,  force  or  boiler  feed-pumps  failing  to  work? 

Locomotive  Engineers. 

Locomotive  engineers  are  not  required  to  furnish  evidence  that 
they  possess  any  theoretical  knowledge ;  nor  are  they  required  to 
pass  any  examination.  They  are  all  employed  in  the  first  place  as 
firemen  or  brakemen,  and  their  promotion  to  the  charge  of  a  loco- 
motive depends  on  their  sobriety,  industry,  and  endurance.  On 
most  railroads  they  are  required  to  fire  from  two  to  three  years ; 
after  which,  if  they  give  evidence  of  sufficient  capacity  and  care- 
fulness, they  are  generally  placed  in  the  repair-shop  or  round- 
house for  one  year,  to  enable  them  to  learn  the  use  of  tools,  but 
more  particularly  to  make  them  acquainted  and  familiar  with  the 
construction  of  the  locomotive  engine,  and  the  manner  of  taking 
its  machinery  apart  and  putting  it  together  again. 

If,  at  the  end  of  three  or  four  years,  he  has  conducted  himself 
properly,  and  given  sufficient  evidence  of  his  knowledge  of  the 
construction  of  a  locomotive  engine  and  its  management  to  make 


THE   engineer's   HANDY-BOOK.  63 

a  good  engineer,  he.  is  promoted  to  a  third-class  engineer.  After 
one  year's  trial  as  third-class  engineer,  if  he  still  gives  evidence 
of  capacity  and  carefulness,  he  is  advanced  to  the  position  of 
second-class.  If,  after  the  expiration  of  one  year  as  a  second- 
class  engineer,  he  is  qualified  in  every  way  for  a  first-class  en- 
gineer, he  is  advanced  to  that  grade;  but  if  not  found  competent, 
he  is  considered  out  of  the  regular  order  of  promotion. 

Steam. 

Steam  is  an  elastic  fluid  resulting  from  the  combination  of  heat 
with  water,  and,  when  the  steam  is  not  in  contact  with  the  water 
from  which  it  is  formed,  it  follows  the  same  general  law  as  all 
other  gases.  This  law  is  as  follows :  All  gases  expand  by  heat  4  ^^th 
part  of  their  volume  for  every  degree  Fah.,  while  their  elastic 
pressure  remains  unaltered,  and  so  long  as  the  temperature  of  a 
gas  remains  unaltered,  its  elastic  pressure  will  vary  inversely  to 
the  volume.  Steam  is  of  several  kinds.  Surcharged  steam  is 
steam  heated  to  a  temperature  higher  than  is  due  to  its  pressure. 
Saturated  steam  is  steam  which,  in  contact  with  the  fluid  from 
which  it  is  formed,  has  brought  with  it  a  proportion  of  moisture. 

Supersaturated  steam  is  steam  in  which  there  is  more  water 
mingled  in  the  form  of  minute  spray  than  is  generally  contained 
in  saturated  steam,  which  is  called  the  water  of  supersaturation. 

The  temperature  of  the  steam  is  always  equal  to  that  of  the 
water  from  which  it  is  formed,  and  the  elastic  force  of  steam 
formed  is  equal  to  the  pressure  under  which  it  is  formed.  The 
elastic  force  of  steam,  barometer  at  30"^,  at  212°  Fah.,  is  one  at- 
mosphere, or  14*7  lbs.  per  sq.  inch;  while  at  250°  Fah.  its  elastic 
force  is  two  atmospheres,  or  29*4  lbs.  per  sq.  inch.  This  includes 
the  pressure  of  the  atmosphere. 

If  the  mercury  be  in  a  vacuum,  the  pressure  of  steam  due  to  a 
temperature  of  212°  Fah.  will  equal  30  inches,  and  for  a  pressure 
due  to  a  temperature  of  250°  Fah.  it  will  equal  60  inches;  but 
if  the  mercury  be  exposed  to  the  atmosphere,  the  pressure  due  to 
250°  Fah.  will  only  equal  30  inches  of  mercury,  and  for  212° 


64 


THE   ENGINEER'S  HANDY-BOOK. 


Fah.  there  is  no  indication  by  a  mercury  gauge,  as  steam  at  212° 
just  balances  the  atmosphere. 

The  volume  of  steam  is  the  space  which  it  occupies.  At  15 
lbs.  pressure  above  atmosphere,  its  volume  is  883,  and  at  30  lbs. 
its  volume  is  610  times  the  space  it  occupied  in  the  shape  of 
water. 

Surcharged  steam  is  not  indicated  by  the  steam-gauge,  as  the 
steam-gauge  only  shows  the  existence  of  pressure ;  but  it  may  be 
indicated  by  a  thermometer  gauge,  or  by  a  fusible  plug. 

If  the  proper  relation  of  the  temperature  between  the  steam  and 
water  be  disturbed,  a  violent  ebullition  or  foaming  will  generally 
take  place,  and  will  continue  till  the  natural  relation  is  restored. 
This  foaming  is  a  source  of  danger  to  the  engine  and  boilers. 

The  total  heat  of  steam  at  212°  Fah.  is  1202°,  of  which  990° 
are  latent  heat,  which  is  heat  that  is  neither  sensible  to  the  touch, 
nor  can  it  be  indicated  by  the  thermometer.  The  existence  of 
this  latent  heat  in  w^ater,  while  in  the  form  of  steam,  may  be 
proved  by  the  following  illustration :  If  5i  lbs.  of  water,  at  32° 
Fah.,  are  placed  in  a  vessel  communicating  with  another,  in  which 
water  is  kept  at  212°  Fah.,  and  kept  there  till  the  former  reaches 
a  temperature  of  212°  Fah.,  and  then  weighed,  it  will  be  found 
to  weigh  6J  lbs.,  showing  that  1  lb.  of  water  has  been  added  to 
the  5i  lbs.  in  the  form  of  steam.  This  pound  of  water,  received 
ic.  the  form  of  steam  had,  w^hen  in  that  form,  a  temperature  of 
212°  Fah.  It  still  possesses  the  same  temperature  of  212°  Fah., 
showing  that  it  has  parted  with  5i  times  the  number  of  degrees 
of  temperature  between  32°  and  212°,  which  is  180,  and  5ixl80 
=  990°.  This  heat  was  combined  with  the  steam,  but  not  being 
.sensible  to  the  thermometer  is  called  latent;  in  this  connection  5i 
is  taken  as  a  convenient  number. 

If  we  observe  the  time  that  a  certain  amount  of  heat  takes  to 
raise  water  from  32°  to  212°,  no  matter  what  the  time  may  be,  it 
will  take  5}  times  as  long  for  the  same  heat  to  evaporate  the  s-ame 
amount  of  water.  It  follows,  that  to  evaporate  water  under  the 
pressure  of  the  atmosphere  requires  5J  times  as  much  heat  as 


THE   ENGINEER'S  HANDY-BOOK. 


65 


would  be  necessary  to  raise  the  same  amount  of  water  from  32''^ 
to  212°. 

A  pound  of  steam  in  passing  from  a  liquid  at  212°  to  steam  at 
212°  receives  as  much  heat  as  would  be  sufficient  to  raise  it 
through  990°,  if  that  heat,  instead  of  being  latent,  had  been  sen- 
sible, and  990°  +  212  =  1202°  is  the  whole  amount  of  the  heat 
in  steam. 

The  latent  heat  of  steam  is  found  by  deducting  its  sensible  heat 
from  1202°. 

TABLE 


SHOWING  THE  INCREASE  OF  SENSIBLE  AND  THE  DECREASE  OF  LATENT 
HEAT  IN  STEAM,  ACCORDING  TO  PRESSURE. 


Gross  Peessuee. 

Sensible  Heat. 

Latent  Heat. 

Relative  Volume. 

15  lbs. 

212° 

966-2° 

1669 

30  " 

251° 

939-0° 

881 

45  " 

275° 

922-7° 

608 

60  " 

294° 

909-2° 

467 

75  " 

309° 

898-5° 

381 

90  " 

320° 

891-3° 

323 

Heat  in  steam  becomes  latent  whenever  a  change  takes  place 
in  the  temperature ;  then  the  heat  produces  the  change,  but  does 
not  raise  the  temperature. 

The  heat  necessary  to  generate  steam,  instead  of  being  212°, 
must  be  966  +  212°  =  1178°  ;  therefore,  the  coal  consumed  and 
the  water  necessary  to  condense  the  steam  must  he  5i  times  as 
great  as  they  would  be,  if  the  heat  were  all  sensible  instead  of 
latent,  which,  it  will  be  observed,  very  materially  affects  the  econ- 
omy of  the  steam-engine. 

The  amount  of  water  necessary  to  condense  a  certain  quantity 
of  steam  may  be  found  as  follows :  If  a  cubic  inch  of  water  pro- 
duces a  cubic  foot  of  steam,  and  the  latent  heat  of  steam  at  212° 
be  taken  at  990^,  or,  in  other  words,  if  the  cubic  foot  of  steam  be 
supposed  to  contain  as  much  heat  in  the  latent  form  as  would 
raise  the  temperature  of  the  cubic  inch  of  water,  if  it  could  be 
6*  E 


66 


THE   ENGINEER'S  HANDY-BOOK. 


prevented  from  expanding,  then  990°,  the  sum  of  the  latent  heat, 
will  be  represented  by  1202°.  The  temperature  of  the  water  dis- 
charged by  the  air-pump  is  about  100°,  which,  deducted  from 
1202°,  leaves  1102°,  which  must  be  taken  up  by  such  a  quantity 
of  cold  water  that  its  temperature  will  not  rise  above  100°.  If 
the  temperature  of  the  injection-water  be  50°,  then  the  difference 
between  that  and  100°  is  50°,  which  is  available  for  the  absorp- 

*  1102° 

tion  of  heat,  and  =  22*1,  which  is  the  number  of  times  the 
injection- water  must  exceed  the  quantity  of  water  in  the  steam. 
Inasmuch  as  the  injection- water  is  seldom  so  cold,  a  much  larger 
proportion  of  injection-water  is  usually  required. 

Steam  which  has  any  elastic  force  not  exceeding  that  of  one 
atmosphere  is  termed  "low  pressure"  steam,  and  "high  pressure" 
is  only  low  pressure  steam  compressed  into  a  smaller  space. 

Surcharged  steam  will  affect  the  vacuum  of  an  engine  on 
account  of  the  undue  amount  of  heat  which  it  contains ;  there- 
fore, the  amount  of  injection-water  must  be  increased  to  take  up 
this  extra  heat,  and  keep  the  condensed  water  at  the  proper  tem- 
perature. 

The  steam  from  salt  water  is  fresh,  because  no  salt  is  carried 
away  in  the  steam  when  evaporation  from  salt  water  takes  place ; 
and  when  the  water  is  all  evaporated,  the  original  salt  will  be 
found  in  the  vessel. 

The  difference  in  volume  between  water  and  steam  at  atmos- 
pheric pressure  is  1669 ;  that  is,  a  given  quantity  of  water,  when 
converted  into  steam,  will  occupy  1669  times  that  which  the  water 
did.  One  cubic  foot  of  steam,  at  atmospheric  pressure,  weighs 
•038  of  a  pound. 

A  steam-jacket  is  a  hollow  casing  surrounding  the  cylinders  of 
steam-engines,  into  which  the  exhaust  steam  is  admitted  in  its 
escape  from  the  cylinder.  Its  object  is  to  preserve  a  uniform 
temperature,  and  to  prevent  radiation  and  condensation.  The 
benefit  to  be  derived  from  its  use,  in  any  case,  is  an  unsettled 
question  among  engineers. 


THE   engineer's  HANDY-BOOK. 


67 


TABLE 

SHOWING  THE  EFFLUENT  VELOCITY  WITH  WHICH  STEAM,  AT  DIFFERENT 
PRESSURES,  WILL  FLOW  INTO  THE  ATMOSPHERE,  OR  INTO  STEAM  AT  A 


LOWER  PRESSURE. 


Pressure  above 
THE  Atmosphere. 

Velocity  of  Escape 
PER  Second. 

Pressuke  above 
THE  Atmosphere. 

Velocity  of  E.scape 
PER  Second. 

Pounds. 

Feet. 

Pounds. 

Feet. 

OU 

1/OD 

2 

698 

60 

1777 

3 

814 

70 

1810 

4 

905 

80 

1835 

5 

981 

90 

1857 

10 

1232 

100 

1875 

20 

1476 

110 

1889 

30 

1601 

120 

1900 

40 

1681 

130 

1909 

Rule  for  Finding  the  Amount  of  Gain  derived  from  Work- 
ing Steam  Expansively. 

Divide  the  length  of  the  stroke  in  feet  by  the  cut-off,  J,  },  i,  as 
the  case  may  be;  then  find  on  the  table  on  page  68  the  hyperbolic 
logarithm  nearest  to  that  of  the  quotient,  to  which  add  1.  This 
sum  will  give  the  ratio  of  gain. 

Example.  —  Suppose  50  pounds  per  square  inch  to  be  the  ini- 
tial pressure ;  length  of  stroke,  10  feet ;  cut-off,  }  ;  find  the  mean 
pressure. 

10  -f-  2-5  =  4.  The  hyperbolic  logarithm  of  4  is  1*38629,  which, 
with  1  added,  becomes  2*38629,  which  is  the  ratio  of  gain. 

4  :  2*38629  : :  50  =  ^'^^^^^  x  50  _  29*82862  lbs.  mean  or  aver- 
4 

age  pressure. 

If  a  given  quantity  of  Steam,  the  expansive  power  of  which,  at 
full  pressure,  is  represented  by  1,  be  admitted  to  a  cylinder  of  a 
certain  size,  and  cut  off  when  the  piston  travels  through  i  of  the 
stroke,  its  effect  will  be  raised  by  expansion  to  1*69 ;  if  cut  off  at 
i,  the  effect  will  be  2*10 ;  at  i  ,  2*39 ;  at  i  2*61 ;  at  i,  2*79 ;  at  i 
2*95  ;  at  i,  3*08  ;  but  the  expansion  cannot  be  carried  beneficially 
as  far  as  i  in  all  classes  of  engines. 


68 


THE  engineer's  HANDY-BOOK. 


TABLE 

OF   HYPERBOLIC   LOGARITHMS  TO  BE  USED  IN   CONNECTION  WITH  THE 

ABOVE  RULE. 


No. 



Logarithm. 

No. 

Logarithm. 

No. 

LOGARITHM. 

1-25 

•22314 

 . 

5- 

1-60943 

9- 

2-19722 

1-5 

•40546 

5-25 

1-65822 

95 

2-25129 

1-75 

•55961 

5-5 

1-70474 

lo- 

2-30258 

2- 

•69314 

5-75 

1-74919 

ll- 

2-39789 

2-25 

.  ^81093 

6- 

1-79175 

12^ 

2-48490 

•  2-5 

•91629 

6-25 

1-83258 

13- 

2-56494 

2-75 

1-01160 

6-5 

1-87180 

14- 

2-63905 

3- 

1-09861 

6-75 

1-90954 

15- 

2-70805 

3-25 

1-17865 

7- 

1-94591 

16- 

2-77258 

3-5 

1-25276 

7-25 

1-98100 

17- 

2-83321 

3-75 

1-32175 

7-5 

2-01490 

18- 

2-89037 

4- 

1-38629 

7-75 

204769 

19- 

2-94443 

4-25 

1-44691 

8- 

2-07944 

20- 

2-99573 

4-5 

1-50507 

8-5 

2  14006 

21- 

3  04452 

4-75 

1-55814 

22- 

3-09104 

Rule  for  finding  the  mean  or  average  pressure  in  the  cylinder 
of  a  steam-engine. 

Divide  the  length  of  the  stroke  in  inches  (including  the  clear- 
ance) by  the  distance  that  the  steam  follows  the  piston  before 
being  cut  off ;  the  quotient  will  be  the  expansion  the  steam  under- 
goes. Then  find  in  the  expansion  column,  in  the  following  table, 
the  number  corresponding  to  it;  take  the  multiplier  opposite,  and 
multiply  the  full  pressure  of  the  steam  per  square  inch,  as  it  enters 
the  cylinder,  by  it.    The  product  will  be  the  average  pressure. 

Example. — Suppose  the  initial  pressure  be  70  lbs.  per  sq.  inch 
and  cut-off  at  half-stroke,  the  stroke  being  3  ft. 

Then  3  ft.  =  36  in.  +  0*5  for  clearance  =  36-5. 
Stroke  J  =  18  in.  +  0-5  "  =  18-5. 
Then  36*5  h-  18*5  =  1*97,  the  relative  expansion  between  1*9 
and  2.  By  referring  to  the  table,  the  multiplier  for  1*9  will  be 
found  to  be  0'864,  and  the  difference  between  that  and  the  multi- 
plier for  2  is  0-017.  Hence,  by  multiplying  0*017  by  '07,  and 
subtracting  the  product  0*011,  the  remainder,  0*86281,  is  the  mul- 
tiplier for  1*97.  Therefore,  0*86281  X  70  =  60*3967  lbs.  per  sq 
inch,  the  mean  effective  pressure  on  the  piston. 


THE   engineer's  HANDY-BOOK. 


69 


TABLE 

OF  MULTIPLIERS  BY  WHICH  TO  FIND  THE  MEAN  PRESSURE  OF  STEAM  AT 


VARIOUS  POINTS  OF  CUT-OFF. 


Expansion. 

Mul  tiplier. 

Expansion. 

Multiplier. 

Expansion . 

MultipllBr. 

10 

1-000 

3-4 

•654 

5^8 

•479 

11 

•995 

3-5 

•644 

5-9 

•474 

1-2 

•985 

3-6 

•634 

6^ 

•470 

.  1-3 

•971 

3-7 

•624 

6^1 

•466 

1-4 

•955 

3-8 

•615 

6^2 

•462  ( 

1-5 

•937 

3-9 

•605 

6-3 

•458 

1-6 

•919 

4- 

•597 

6-4 

•454 

1-7 

•900 

4-1 

•588 

6^5 

•450 

1-8 

•882 

4^2 

•580 

6^6 

•446 

1-9 

•864 

4*3 

•572 

6^7 

•442 

2- 

•847 

4-4 

•564 

6-8 

•438 

2-1 

•830  • 

4-5 

•556 

6^9 

•434 

2-2 

•813 

4-6 

•549 

7' 

•430 

2-3 

•797 

4-7 

•542 

7-1 

•427 

2-4 

•781 

4-8 

•535 

7^2 

•423 

2-5 

•766 

4-9 

•528 

7^3 

•420 

2*6 

•752 

5* 

•522 

7  4 

417 

2-7 

•738 

5-1 

•516 

75 

•414 

2-8 

•725 

5-2 

•510 

7^6 

•411 

2-9 

•712 

.  5-3 

•504 

7-7 

•408 

3- 

•700 

5-4 

•499 

7^8 

•405 

3-1 

•688 

5-5 

•494 

7^9 

•402 

3-2 

•676 

5-6 

•489 

8^ 

•399 

3*3 

•665 

5-7 

•484 

TABLE 

OF  CONSTANT  NUMBERS,  BY  WHICH  TO  ASCERTAIN  THE  AVERAGE  PRESS- 
URE OF  THE  STEAM  AGAINST  THE  PISTON  FOR  DIFFERENT  PRESSURES 
AND  POINTS  OF  CUT-OFF,  FROM  i  TO  |  OF  THE  STROKE. 


Point  of  Cut-off. 

Constant  Number. 

Point  of  Cut-off. 

Constant  Number. 

1 

4 

•5965 

5 

•9188 

1 

3 

•6995 

2 
3 

•9370 

3 

E 

2 

•7428 

3 
4 

•9657 

•8465 

7 

H 

•9919 

Multiply  the  pressure  in  pounds,  as  shown  by  the  gauge,  by  the 
constant  number  opposite  the  point  of  cut-off  in  the  left  column. 
The  product  is  the  average  pressure. 


70  THE  ENGINEER'S  HANDY-BOOK. 


TABLE 

OF  CONSTANT  NUMBERS  FOR  FINDING  THE  REQUIRED  "lAP"  FOR  SLIDE- 
VALVES,  WHEN  THE  TRAVEL  OF  THE  VALVE  IS  KNOWN. 


Cut-off 

1 

7 

2 
3 

_3 
4 

5 
6 

i 

1 1 

T3 

Multiplier. 

•354 

•323 

•289 

•250 

•204 

•177 

•144 

Multiply  the  valve-stroke  by  the  decimals  opposite  each  point 
of  cut-off. 

There  are  two  methods  of  applying  the  power  of  steam  to  the 

cylinders  of  steam-engines,  one  being  to  allow  it  to  flow  from  the 
boiler  to  the  cylinder  through  the  whole  length  of  the  stroke,  the 
other  to  cut  off  the  supply  when  the  piston  has  travelled  a  certain 
distance.  The  advantage  of  the  latter  over  the  former  consists 
in  the  saving  of  fuel;  which  may  be  explained  as  follows;  If 
steam  be  applied  the  full  length  of  the  stroke,  the  average  press- 
ure will  be  as  the  pressure  per  square  inch  on  the  piston ;  but  if 
the  steam  be  cut  off  at  half  stroke, —  suppose  the  pressure  to  be 
65  lbs.  per  square  inch,  when  the  pressure  of  the  atmosphere  is 
added, —  there  will  be  a  mean  equivalent,  or  average  pressure, 
throughout  the  stroke  of  about  55  lbs.  per  square  inch,  being  only 
10  lbs.  less  than  full  pressure,  or  16  per  cent,  of  a  loss  in  power, 
though  only  half  the  former  quantity  of  steam  has  been  used. 

Steam-ports. —  A  term  applied  to  the  passages  through  which 
the  steam  enters  the  cylinder ;  they  are  generally  the  area  of 
the  piston,  but  vary  for  different  boiler  pressures  and  piston  speeds, 
those  of  locomotives  being  about  jq,  which  have  the  largest  ports 
of  any  class  of  engines.  The  area  of  the  exhaust-port  should  be 
from  ^  to  ^  that  of  the  cylinder.  As  a  rule,  the  exhaust,  when 
passing  out  of  the  cylinder  after  the  first  rush  is  over,  should  not 
have  to  travel  faster  than  100  feet  per  second  ;  but  with  some  de- 
signs of  engines  the  velocity  of  the  steam  may  be  greater,  without 
creating  injurious  back  pressure.  The  form  of  the  ports  is  imma- 
terial, providing  they  are  large  enough  to  give  admission  to  the 
amount  of  steam  requisite  to  keep  the  pressure  up  to  its  initial  point 
until  it  is  cut  off  by  the  valve,  and  give  free  egress  for  its  escape. 


THE   ENGINEER'S   H  AN  D  Y-BOO  JC  . 


TABLE 

SHOWING  THE  AVERAGE  PRESSURE  OF  THE  STEAM  UPON  THE  PISTON 
THROUGHOUT  THE  STROKE,  WHEN  CUT  OFF  IN  THE  CYLINDER  FROM 
J  TO  I,  COMMENCING  WITH  10  POUNDS  AND  ADVANCING  IN  5  POUNDS 
UP  TO  55  POUNDS  PRESSURE. 


Pressure  in  Pounds  at  the  Commencement  of  the  Stroke. 

10 

15 

20 

25 

30 

35 

40 

45 

50 

55 

Average  Pressure  in  Pounds  upon  the  Piston. 

7 

lOi 

14} 

±'±2 

X 1  2 

24* 

28 

SI  * 

0x2 

35 

.Sf^* 

00  2 

O  4 

14 

181 

^0  2 

281 

87  i 
012 

42 

46?^ 

51  i 

9 

12 

15 

17f 

201 

281 

26f 

291 

821 

89 
vJ  2 

121 

17 

21 

251 

29^ 

331 

88 

421 

46^ 

U  2 

14^ 

191 

24 

281 

00  2 

38} 

481 

58 

lOi 

15} 

18J 

20  i 

23} 

^^6 

28} 

1  2 

X  J.  2 

151 

19 

28 

261 

80  i 

84i 

881 
0U4 

49 

Q 

£7 

13 

18 

2 

97 

81^ 

861 

OU  4 

40^ 

451 

49^ 

91 

14i 

19J 

231 

29} 

34} 

39 

44 

49 

53J 

4i 

7 

9} 

m 

14 

16} 

18i 

20i 

23} 

25  i 

91 

lii 

191 

24i 

29  J 

B4i 

39J 

44} 

49} 

54 

4i 

6i 

.8} 

lOi 

12* 

Ui 

161 

181 

21 

23} 

6J 

9i 

I2i 

16 

19} 

22i 

261 

281 

32 

35} 

71 

111 

155 

191 

231 

27  i 

31  i 

35^ 

39* 

m 

81 

m 

171 

22} 

261 

31} 

35J 

40 

44* 

49 

9i 

Ui 

19 

23i 

281 

33* 

38} 

421 

47  i 

d2i 

91 

14i 

191 

241 

29  i 

34i 

39i 

44* 

49* 

54} 

31 

5? 

71 

9i 

11* 

13* 

15} 

17} 

19} 

21} 

7^ 

11 

143- 

18i 

22} 

26 

29J 

33i 

37 

401 

9i 

131 

18} 

221 

27* 

32 

36f 

41} 

45* 

501 

9i 

141 

m 

24i 

29i 

341 

39* 

44^ 

49* 

54J 

M  <3J  0) 

s  6" 


72  THE   ENGINEER'S  HANDY-BOOK. 


TABLE 

SHOWING  THE  AVERAGE  PRESSURE  OF  THE  STEAM  UPON  THE  PISTOH 
THROUGHOUT  THE  STROKE,  WHEN  CUT  OFF  IN  THE  CYLINDER  FROM 
J  TO  I,  COMMENCING  WITH  60  POUNDS  AND  ADVANCING  IN  5  POUNDS 
UP  TO  105  POUNDS  PRESSURE. 


5« 

^  ^; 

Pressure  in  Pounds  at  the  Commencement  of  the  Stroke. 

a 

60 

65 

70 

75 

80 

85 

90 

95 

100 

105 

m 

Average  Pressure  in  Pounds  upon  the  Piston. 

1 

3 

2 
3 

1 
4 
1 

4 

i 

2 
5 

1 

4 

5 

1 

6 

1 

7 

3 
7 

4 
7 

5 
T 

6 

1 

5 
3 

5 
5 

1  * 

42 

56  i 

351 

501 

57f 

3U 

46 

54} 

58J 

27i 

59 

25} 

S8i 

47i 

53J 

57} 

59} 

23 

Ui 

55} 

59  J 

45i 

61 

381 

55 

62^ 

34 

491 

581 

6Si 

30} 

64 

27} 

411 

511 

571 

62 

63i 

25 

48} 

591 

64i 

49 

65J 

411 

69} 

67i 

B6i 

53i 

63} 

G8i 

S2i 

69 

29} 

45 

55i 

62} 

661 

69} 

27 

52 

641 

69i 

52} 

70} 

44i 

63} 

72} 

39 

57} 

67i 

731 

341 

73f 

31} 

48} 

59} 

661 

71} 

74} 

28f 

55J 

68! 

74} 

56 

75 

471 

671 

77} 

4li 

61} 

72} 

78} 

37} 

781 

33} 

51} 

63} 

71} 

76} 

79 

30i 

59} 

73} 

79} 

59} 

79} 

501 

72 

82 

44} 

65 

77 

83 

39} 

831 

351 

54} 

67} 

751 

81 

84 

321 

63 

78 

84} 

63 

84} 

53i 

76} 

87 

47 

69 

81} 

88 

41  i 

881 

37i 

57i 

71} 

80 

851 

89 

34} 

66i 

82} 

89} 

66} 

89 

561 

80} 

91i 

49} 

72i 

86 

921 

44} 

93} 

40 

61 

75} 

84} 

901 

931 

36} 

70} 

87} 

94} 

70 

931 

591 

841 

96} 

52} 

76} 

90} 

97i 

46} 

98} 

42 

64} 

79 

89 

95} 

98-1 

38} 

74} 

91f 

99 

73 
98} 
621 
89 

101} 
54i 
80} 
95} 

102f 
481 

103} 
44 
67} 
83  . 
93} 

100} 

103f 
40} 
78 
96} 

104 

THE   engineer's   HANDY-BOOK.  73 


TABLE 

SHOWING  THE  AVERAGE  PRESSURE  OF  THE  STEAM  UPON  THE  PISTON 
THROUGHOUT  THE  STROKE,  WHEN  CUT  OFF  IN  THE  CYLINDER  FROM 
J  TO  J,  COMMENCING  WITH  110  POUNDS  AND  ADVANCING  IN  5  POUNDS 
UP  TO  150  POUNDS  PRESSURE. 


m  cut  off 
in  the 
y^linder. 

•  Pressure  in  Pounds  at  the  Commencement  of  the  Stroke. 

no  1 

115  j 

120 

125 

130 

135 

140 

145 

1  150 

Average  Pressure  in  Pounds  upon  the  Piston. 

1 

3 
o 
% 

1 

4 

3 
4 

i 

2 

3 
5 

4 

'5 

1 

<S 

5 
6 
1 

T 

2 
7 

4 

T 
5 
7 

6 
7 

1 

3 

5 
■g" 
7 
H 

77i 

103 
65  J 
93  i 

106} 
57} 
84} 

m 

1071 
51} 
108} 
46} 
70} 
87 
98 
105 
108} 
42} 
81} 
101 
109 

80  i 
107} 

m 

97} 
111 

60 

88 
104} 

im 

53  i 
113} 
48} 
74 
91 

102i 
1091 
113} 

m 

85} 
105i 
114 

84 
112i 

m 

lOli 
115} 
62i 
911 
1081 
117i 
551 
118} 
50i 
771 
94} 
1061 
114* 
118} 
46} 
89 
110} 
119 

87  i 
117 

74} 
105} 
120} 

65} 

95} 
113} 
122} 

58 

123} 
52} 
80} 
98} 
111} 
119} 
123* 
48 
92} 
114} 
124 

91 

121} 
77} 
110 
125} 
67} 
99} 
117} 
127} 
60} 
128 
64} 
83} 
102} 
115} 
124 
128* 
50 
96* 
119* 
128} 

94} 
126} 

80} 
114} 
130} 

70} 
103} 
122} 
132 

62} 
133 

561 

861 
106} 
120} 
128} 
133* 

52 
100} 
124 
133} 

98 
131 

83} 
118} 
135} 

73 
107} 
126} 
136} 

65 
137} 

58} 

90 
110} 
124} 
133} 
138* 

54} 
104 
128* 
138} 

101} 
135} 

86} 
122} 
140 

75} 
111 
131} 
141} 

67} 
142} 

61 

93} 
114} 
129} 
138* 
143* 

56} 
107} 
133} 
143} 

105 
140} 

89} 
127 
144} 
'  78} 
115 
135 
146} 

69} 
147 

63 

96} 
118} 
133} 
143} 
148} 

571 
111* 
137} 
148} 

7 


74 


THE   ENGINEER'S  HANDY-BOOK. 


TABLE 

SHOWING  THE  TEMPERATURE  OF  STEAM  AT  DIFFERENT  PRESSURES,  FROM 
1  LB.  PER  SQUARE  INCH  TO  220  LBS.,  AND  THE  QUANTITY  OF  STEAM 
PRODUCED  FROM  A  CUBIC  INCH  OF  WATER,  ACCORDING  TO  PRESSURE. 


It  is  necessary  to  add  the  pressure  of  the  atmosphere,  15  pounds,  to  the  pressure  on 
the  steam-gauge,  to  correspond  with  the  table. 


Total 
Pressure 
oi  C5it;aiii 
in  lbs.  per 
Square 
Inch. 

Correspond- 
ing Temper- 
ature of 
Steam  to 
Pressure. 

Cubic  Inches 
of  Steam  from 
a  Cubic  Inch 

of  Water 
according  to 

Pressure. 

Total 
Pressure 

in  lbs.  per 
Square 
Inch. 

Correspond- 
ing Temper- 
ature of 
Steam  to 
Pressure. 

Cubic  Inches 
of  Steam  from 
a  Cubic  Inch 

of  Water 
according  to 

Pressure. 

1 

102-90 

20868 

29 

249-60 

911 

2  ■ 

126-1 

10874 

30 

251-6 

883 

3 

141-0 

7437 

31 

253-6 

857 

4 

152-3 

5685 

32 

255-5 

833 

5 

161-4 

4617 

33 

257-3 

810 

6 

169-2 

3897 

34 

259-1 

788 

7 

175-9 

3376 

35 

260-9 

767 

182-0 

2983 

36 

262-6 

748 

9 

187-4 

2674 

37 

264-3 

729 

10 

192-4 

2426 

38 

265-9 

712 

11 

197-0 

2221 

39 

267-5 

695 

12 

201-3 

2050 

40 

269-1 

679 

13 

205-3 

1904 

41 

270-6 

664 

14 

209-1 

1778 

42 

272-1 

649 

15 

212-8 

1669 

43 

273-6 

635 

16 

216-3 

1573 

44 

275-0 

622 

17 

219-6 

1488 

45 

276-4 

610 

18 

222-7 

1411 

46 

277-8 

598 

19 

225-6 

1343 

47 

279-2 

586 

20 

228-5 

1281 

48 

280-5 

575 

21 

231-2 

1225 

49 

281-9 

564 

22 

233-8 

1174 

50 

283-2 

554 

23 

236-3 

1127 

51 

284-4 

544 

24 

238-7 

1084 

52 

285-7 

534 

25 

241-0 

1044 

53 

286-9 

525 

26 

243-3 

1007 

54 

288-1 

516 

27 

245-5 

973 

55 

289-3 

508 

1  28 

247-6 

941 

56 

290-5 

500 

THE   engineer's  HANDY-BOOK. 


75 


TABLE 

SHOWING  THE  TEMPERATURE  OF  STEAM  AT  DIFFERENT  PRESSURES,  FROM 
1  LB.  PER  SQUARE  INCH  TO  220  LBS.,  AND  THE  QUANTITY  OF  STEAM 
PRODUCED  FROM  A  CUBIC  INCH  OF  WATER,  ACCORDING  TO  PRESSURE. 


It  is  necessary  to  add  the  pressure  of  the  atmosphere,  15  pounds,  to  the  pressure  on 
the  steam-gauge,  to  correspond  with  the  table. 


Total 
Pressure 
01  bieam 
in  lbs.  per 
Square 

Inch. 

Correspond- 
ing Temper- 
ature of 

Pressure. 

Cubic  Inches 
of  Steam  from 
a  Cubic  Inch 

of  Water 
according  to 

Pressure. 

Total 
Pressure 
of  Steam 
in  lbs.  per 
Square 
Inch. 

Correspond- 
ing Temper- 
ature of 

Pressure. 

Cubic  Inches 
of  Steam  from 
a  Cubic  Inch 

of  Water 
according  to 

Pressure. 

57 

291 -70 

492 

85 

"  320-10 

342 

58 

292-9 

484 

86 

321-0 

339 

59 

294-2 

477 

87 

321-8 

335 

60 

295-6 

470 

88 

322-6 

332 

61 

296-9 

463 

89 

323-5 

328 

62 

298-1 

456 

90 

324-3 

325 

63 

299-2 

449 

91 

325-1 

322 

64 

300-3 

443 

92 

325-9 

319 

65 

301-3 

437 

93 

326-7 

316 

66 

302-4 

431 

94 

327-5 

313 

67 

303-4 

425 

95 

328-2 

310 

68 

304-4 

419 

96 

329-0 

307 

69 

305-4 

414 

97 

329-8 

304 

70 

306-4 

408 

98 

330-5 

301 

.71 

307-4 

403 

99 

331-3 

298 

72 

308-4 

398 

100 

332-0 

295 

73 

309-3 

393 

110 

339-2 

271 

74 

310-3 

388 

75 

311-2 

383 

130 

352-1 

233 

76 

312-2 

379 

140 

357-9 

218 

77 

313-1 

374 

150 

363-4 

205 

78 

314-0 

370 

160 

368-7 

193 

79 

314-9 

366 

170 

373-6 

183 

80 

315-8 

362 

180 

378-4 

174 

81 

316-7 

358 

190 

382-9 

166 

82 

317-6 

354 

200 

387-3 

158 

83 

.  318-4 

350 

210 

391-5 

151 

84 

319*3 

346 

220 

395-5 

145 

 .  » 

76 


THE   engineer's  HANDY-BOOK. 


Explanation  of  the  following  Table. 

The  first  column  gives  the  absolute  pressure  of  the  steam  in 
inches  of  mercury,  or  the  height  to  which  the  pressure  would  raise 
a  column  of  mercury  in  a  tube,  provided  the  opposing  pressure 
of  the  atmosphere  were  removed. 

The  second  column  gives  the  absolute  pressure  in  pounds  per 
square  inch  under  the  same  circumstances. 

The  third  column,  it  will  be  observed,  is  headed  "Pressure 
above  Atmosphere."  By  this  is  meant  the  apparent  pressure  of 
the  steam  as  indicated  by  a  steam-gauge. 

The  fourth  column  shows  the  temperature  in  degrees  of  Fah' 
renheit's  scale. 

The  fifth  column  shows  the  increase  of  volume  which  the  water 
assumes  in  the  act  of  changing  into  steam. 

The  sixth  column  shows  the  velocity  with  which  steam,  at  the 
given  pressures,  escapes  through  an  orifice  into  the  atmosphere,  as, 
for  example,  through  the  safety-valve  of  a  steam-boiler. 

TABLE 

OF  THE  ELASTIC  FORCE,  TEMPERATURE,  AND  VOLUME  OF  STEAM  FROM  A 
TEMPERATURE  OF  32°  TO  457°  FAH.,  AND  FROM  A  PRESSURE  OF  0*2  TO 
900  INCHES  OF  MERCURY. 


ELASTIC  FORCE  IN 

Pressure 
above 
Atmosphere. 

Temper- 
ature. 

Volume. 

Velocity  of 
Escape. 

Inches  of 

Pounds  per 

Mercury. 

Square  Inch. 

•200 

•098 

32° 

187407 

•221 

•108 

35 

170267 

•263 

•129 

40 

144529 

•316 

•155 

45 

121483 

•375 

•184 

50 

103350 

•443 

•217 

55 

88388 

,  ^524 

•257 

60 

75421 

•616 

•302 

65 

64762 

•721 

•353 

70 

55862 

1  '851 

•417 

75 

47771 

rooo 

•490 

80 

41031 

THE  engineer's  HANDY-BOOK. 


77 


TABLE 

(IF  THE  ELASTIC  FORCE,  TEMPERATURE,  AND  VOLUME  OF  HTP:AM  FROM  A 
TEMPERATURE  OF  32°  TO  457°  FAH.,  AND  FROM  A  PRESSURE  OF  0*2  TO 
900  INCHES  OP  MERCURY. 


ELASTIC  FORCE  IN 

Pressure 
above 
Atmosphere. 

Temper- 
ature. 

Volume. 

Velocity  of 
Escape. 

Inches  of 
Mercury, 

Pounds  per 
Square  Inch. 

1-17 

•573 

85-° 

35393 

1-36 

•666 

90- 

30425 

1-58 

•774 

95- 

26686 

1-86 

•911 

100- 

22878 

2-04 

1-000 

103- 

20958 

2-18 

1-068 

105- 

19693 

2-53 

1-24 

110^ 

16667 

2-92 

1-431 

115- 

14942 

3-33 

1-632 

120- 

13215 

3-79 

1-857 

125* 

11723 

4-34 

2-129 

130- 

10328 

5-00 

2-45 

135- 

9036 

5-74 

2-813 

140- 

7938 

6-53 

3-100 

145* 

7040 

7-42 

3-636 

150- 

6243 

8-40 

4116 

155- 

5559 

9-46 

4-635 

160- 

4976 

10-68 

5-23 

165- 

4443 

12-13 

5-94 

170- 

3943 

13-62 

6-67 

175* 

3538 

15-15 

7-42 

180- 

3208 

17-00 

8-33 

185- 

2879 

19-00 

9-31 

190* 

2595 

21-22 

10-40 

195- 

2342 

23-64 

11-58 

200- 

2118 

26*13 

205- 

1932 

28-84 

14-13 

210- 

1763 

29-41 

14-41 

211- 

17S0 

30-00 

14-70 

0- 

212- 

1700 

30-60 

15-00 

212-8 

1669 

3L62 

15-50 

0-8 

214-5 

1618 

32-64 

16-00 

1-3 

216-3 

1573 

33-66 

16-50 

218- 

1530 

34-68 

17-00 

2-3 

219-6 

1488 

35-70 

17-50 

221*2 

1440 

36-72 

18-00 

3-3 

222-7 

1411 

37-74 

18-50 

224-2 

1377 

874 

38-76 

19-00 

4-3 

225-6 

1343 

7* 


78 


THE  ENGINEER'S  HANDY-BOOK. 


TABLE 

OF  THE  ELASTIC  FORCE,  TEMPERATURE,  AND  VOLUME  OF  STEAM  FROM  A 
TEMPERATURE  OF  32°  TO  457°  FAH..  AND  FROM  A  PRESSURE  OF  0*2  TO 
900  INCHES  OF  MERCURY. 


ELASTIC  ] 

Inches  of 
Mercury. 

FORCE  IN 

Pounds  per 
Square  Inch. 

Pressure 
above 
Atmosphere. 

Temper- 
ature. 

Volume. 

Velocity  of 
Escape. 

39*78 

19*50 

227*1° 

1312 

40*80 

20*00 

5*3 

228*5 

1281 

41*82 

20*50 

229*9 

1253 

42*84 

21*00 

6-3 

231*2 

1225 

43*86 

21*50 

232*5 

1199 

44*88 

22*00 

7'3 

233*8 

1174 

1136 

45*90 

22*50 

235*1 

1150  ( 

46*92 

23*00 

8*3 

236*3 

1127 

47*94 

23*50 

237*5 

1105 

48*96 

24*00 

9*3 

238*7 

1084 

49*98 

24*50 

239*9 

1064 

51*00 

25*00 

10*3 

241* 

1044 

53*04 

26*00 

11*3 

243*3 

1007 

1295 

55*08 

27* 

12*3 

245*5 

973 

57*12 

28* 

13*3 

247*6 

941 

59*16 

29' 

14*3 

249*6 

911 

1407 

61*20 

30* 

15*3 

251*6 

883 

63*24 

31- 

16*3 

253*6 

857 

65*28 

32* 

17*3 

255*5 

833 

67*32 

33* 

18*3 

257*3 

810 

1491 

69*36 

34* 

1D*3 

259*1 

788 

71*40 

35* 

20-3 

260*9 

767 

73*44 

36- 

21-3 

262*6 

748 

75*48 

37- 

22*3 

264*3 

729 

1550 

77*52 

38* 

23*3 

265*9 

712 

79*56 

39* 

24*3 

267*5 

695 

81*60 

40* 

25*3 

269*1 

679 

1600 

83*64 

41- 

26-3 

270-6 

664 

85*68 

42- 

27-3 

272*1 

649 

87*72 

43- 

28*3 

•  273*6 

635 

89*76 

44* 

29-3 

275* 

622 

1652 

91*80 

45* 

30*3 

276*4 

610 

93*84 

46* 

31-3 

277*8 

598 

95*88 

47- 

32-3 

279*2 

586 

97*92 

48* 

33-3 

280*5 

575 

1690 

99*96 

49* 

34-3 

281*9 

564 

102*00 

50* 

35-3 

283*2 

554 

104-04 

51* 

36-3 

284*4 

544 

1720 

THE   engineer's  HANDY-BOOK. 


79 


TABLE 


OF  THE  ELASTIC  FORCE,  TEMPERATURE,  AND  VOLUME  OF  STEAM  FROM  A 
TEMPERATURE  OF  32°  TO  457°  FAH.,  AND  FROM  A  PRESSURE  OF  0  2  TO 
900  INCHES  OF  MERCURY. 


ELASTIC  ] 

Inches  of 
Mercury. 

FORCE  IN 

Pounds  per 
Square  Inch. 

Pressure 
above 
Atmosphere. 

Temper" 
ature. 

Volume. 

- 

VClUl^lliJf  til 

Escape. 

J.UU  \JO 

K9' 

O  I  o 

9ft.'=»*7° 

l\JO  ±Zj 

oo 

on  o 

9ftfi*Q 

J-IU  J.U 

tit 

ou  o 

^OO  1 

.'^Ifi 

119-90 

OUO 

1 7.^ 

1  <  OU 

114*24 

56* 

41 -i? 

290*5 

ouu 

1  lfi*9ft 

O  4 

9Q1  '7 

dQ9 

118'32 

58* 

9Q9*Q 

ri:Cr± 

1774. 

120*36 

59* 

9Q4--9 

4-77 

122*40 

295*6 

4.70 

*x  1  U 

fil  • 

9QR'Q 

TbOO 

126*48 

*  1 

9QR*1 

4^U 

128  52 

uo 

rt(j  *9 

9QQ*9 

44.Q 

130*66 

ut 

^00*^ 

ouu  o 

132*60 

^01  *^ 

4J^7 

-to  i 

134*64 

uu 

4-^1 
toi 

lOlD 

136*68 

67* 

303*4 

o 

138*72 

68* 

304*4 

4.1  Q 

140*76 

69* 

OUti  rr 

4.14. 

142*80 

70* 

4.0ft 

144*84 

71* 

.^07 '4. 

10^ 
iUO 

146*88 

79* 

If  •  o 

OUO  *! 

148*92 

<  O 

ouc  o 

IRriO 
JooU 

150*96 

74-* 

OIU  o 

oOO 

153*02 

7^* 

^1 1  '9 

oil  ^ 

QftQ 

OOO 

155*06 

7fi* 

Ol  o 

^19*9 

^7Q 

157*10 

77* 

^1  ^'1 

o/4 

7«* 

oo  o 

olt 

Q7n 
o<U 

161*18 

79- 

64-3 

314*9 

366 

163*22 

80* 

65-3 

315*8 

.  362 

165*26 

81- 

6f>-3 

316*7 

358 

167*30 

82* 

67-3 

317*7 

354 

169*34 

83* 

68-3 

318*4 

350 

171*38 

84* 

69-3 

319*3 

346 

173*42 

85* 

70-3 

320*1 

342 

183*62 

90- 

75-3 

324*3 

325 

1904 

193*82 

95* 

80-3 

328*2 

310 

203*99 

100* 

85-3 

332* 

1195 

214*19 

105* 

90-3 

335*8 

282 

1950 

80 


THE   engineer's  HANDY-BOOK. 


TABLE 

OF  THE  ELASTIC  FORCE,  TEMPERATURE,  AND  VOLUME  OF  STEAM  FROM  A 
TEMPERATURE  OF  32°  TO  457°  FAH.,  AND  FROM  A  PRESSURE  OF  0*2  TO 
900  INCHES  OF  MERCURY. 


ELASTIC 

T 

Inches  of 
Mercury. 

FORCE  IN 

Pounds  per 
Square  Inch. 

Pressure 
above 
Atmosphere. 

ature. 

Volume. 

Velocity  01 
Escape. 

224-39 

110- 

95-3 

339-2° 

271 

234-59 

115- 

100-3 

342-7 

259 

244-79 

120- 

105-3 

345-8 

251 

1980 

254-99 

125- 

110-3 

349-1 

240 

265-19 

130- 

115-3 

352-1 

233 

275-39 

135- 

120-3 

355- 

224 

2006 

285-59 

140- 

125-3 

357-9 

218 

295-79 

145- 

130-3 

360-6 

210 

306- 

150- 

135-3 

363-4 

205 

2029 

316-19 

155- 

140-3 

366- 

198 

326-29 

160- 

145-3 

368-7 

193 

336-59 

165- 

150-3 

371-1 

187 

346-79 

170- 

155-3 

373-6 

183 

357- 

175- 

160-3 

376- 

178 

367-2 

180- 

165-3 

378-4 

174 

377-1 

185- 

170-3 

380-6 

169 

2074 

387-6 

190- 

175-3 

382-9 

166 

397-8 

195- 

180-3 

384-1 

161 

408- 

200- 

185-3 

387-3 

158 

448-8 

220- 

205-3 

392- 

2109 

524-28 

257- 

242-3 

406- 

2136 

599-76 

294- 

279-3 

418- 

2159 

848-68 

367- 

352-3 

429- 

2196 

889-64 

441- 

426-3 

457- 

2226 

It  will  be  observed  that  in  the  foregoing  and  following  tables 
the  relative  volume  and  weight  of  steam  differs  with  different 
authors,  and,  while  they  may  not  all  be  scientifically  correct, 
they  are  undoubtedly  approximately  so,  or  suflSciently  correct 
for  all  practical  purposes.  Therefore,  it  would  be  perfectly  safe 
to  take  the  volume  of  steam  at  1728 ;  in  other  words,  a  cubic 
inch  of  water  converted  into  stearii  at  atmospheric  pressure  will 
occupy  1728  cubic  inches,  or  one  cubic  foot. 


THE   engineer's  HANDY-BOOK. 


81 


TABLE 

Showing  the  temperature  and  weight  of  steam  at  differeni. 
i-ressures  from  1  pound  per  square  inch  to  300  pounds,  ani, 

'ajHE  quantity  of  steam  produced  from  1  CUBIC  INCH  OF  WATER, 


ACCORDING  TO  PRESSURE. 


Total  Pressure 
per  Square  Inch 
measured  from 
a  Vacuum. 

Pressure 
above  At- 
mosphere. 

Sensible 
Tem  peratu  re 
in  Fahren- 
heit degrees. 

lotal  Heat  in 
Degrees  from 
Zero  of  Fah- 
renheit. 

Weight  of 
one  Cubic 
Foot  of 
Steam. 

Relative  Volume 
of  Steam  com-  | 

pared  with  Water 
from  which  it  ( 

was  raised.  i 

1 

1 

102-1 

1144-5 

-0030 

20582 

2 

126-3 

1151-7 

-0058 

10721 

3 

141-6 

1156-6 

•0085 

7322 

4 

153-1 

1160-1 

-0112 

5583 

5 

162-3 

1162-9 

-0138 

4527 

6 

170-2 

1165-3 

-0163 

3813 

7 

176-9 

1167-3 

-0189 

3298 

8 

182-9 

1169-2 

-0214 

2909 

9 

188-3 

1170-8 

•0239 

2604 

10 

193-3 

1172-3 

•0264 

2358 

11 

197-8 

1173-7 

•0289 

2157 

12 

2020 

11750 

•0314 

1986 

13 

205-9 

1176-2 

•0338 

1842 

14 

209-6 

1177-3 

•0362 

1720 

14-7 

0 

212-0 

11781 

•0380 

1642 

15 

•3 

213-1 

1178-4 

-0387 

1610 

16 

1-3 

216-3 

1179-4 

•0411 

1515 

17 

2-3 

219-6 

1180-3 

•0435 

1431 

18 

3-3 

222-4 

1181-2 

•0459 

1357 

19 

4-3 

225-3 

1182-1 

•0483 

1290 

20 

5-3 

228-0 

1182-9 

•0507 

1229 

21 

6-3 

230-6 

1183-7 

•0531 

1174 

22 

7-3 

233-1 

1184-5 

•0555 

1123 

23 

8-3 

235-5 

1185-2 

•0580 

1075 

24 

9-3 

237-8 

1185-9 

•0601 

1036 

25 

10-3 

240-1 

1186-6 

•0625 

996 

26 

11-3 

242-3 

1187-3 

•0650 

958 

27 

12-3 

244-4 

1187-8 

•0673 

926 

28 

13-3 

246-4 

1188-4 

•0696 

895 

29 

14-3 

248-4 

1189-1 

-0719 

866 

30 

15-3 

250-4 

1189-8 

-0743 

838 

31 

1.6*3 

252-2 

1190-4 

-0766 

813 

32 

17*3 

254-1 

1190-9 

-0789 

789 

33 

18-3 

255-9 

1191-5 

-0812 

767 

«  34 

19-3 

257-6 

1192-0 

-0835 

746 

35 

20-3 

259-3 

1192-5 

-0858 

726 

36 

21-3 

260-9 

1193-0 

-0881 

707 

37 

22-3 

262-6 

1193-5 

•0905 

688 

38 

23-3 

264-2 

1194-0 

•0929 

671 

39 

24-3 

265-8 

1194-5 

-0952 

655 

F 


82  THE  engineer's  handy-book. 


TABLE  —  ( Continued. ) 


Total  Pressure 
per  Square  Inch 
measured  from 
a  Vacuum. 

Pressure 
above  At- 
mosphere. 

Sensible 
Temperature 
in  Fahren- 
heit degrees. 

Total  Heat  in 
Degrees  from 
Zero  of  Fah- 
renheit. 

Weight  of 
one  Cubic 

i;  OOlr  01 

Steam. 

Relative  Volume 

of  Steam  com- 
pared with  Water 
from  which  it 
was  raised. 

ZiO  0 

1 10d*Q 

•0074 

A40 
U4U 

At 

9A'^ 

9Aft*7 

llaO  4 

•OOOfi 

uzo 

97.0 

1 1Qn:.Q 
llc/O  0 

•1090 
lUZU 

A1 1 
oil 

'±0 

971  'A 

1 10A*9 
1  lyu  z 

•1049 
1U4Z 

'^Oft 

A4 
4^ 

9Q'Q 

97q*n 

Zi  0  u 

1 10A*A 

•lOA^ 
lUDO 

OuO 

4:0 

oU  0 

Z/4  4 

1 107*1 

•lOftO 

04  z 

A(\ 

ol  0 

97'=;*ft 

ZrO  0 

1 107*^ 

11(7  1  0 

*1 1 1 1 

1111 

f^AI 

OUX 

A7 

09. q 

977*1 
z/  /  1 

1 107*0 

*1 1 

lloo 

oou 

Aft 

qq.q 

00  0 

97ft*zL 
^< 0  4 

1 10ft*^ 
1 1  aO  0 

•1 1 

1100 

00«7 

AO 

qzl«q 

97Q'7 

1 10ft'7 

•1 170 

Ilia 

^9Q 

OZi7 

ou 

9ft  1  -n 

1 100*1 

1  luo  1 

•1 909 

IZUZ 

010 

01 

qA*^ 

9ft9*^ 

1  ivv  0 

•1  994 

1ZZ4 

'^OO 

OUt7 

q7.q 

9ftq*'^ 

1 100*0 

•1 94fi 

1Z4D 

^00 

OUU 

OO 

^ft*^ 

00  0 

9ftA*7 
Zo4  < 

IZUU  0 

•19AQ 

4Q1 

04 

qQ*Q 

9ft'=;*Q 

ZoO  1/ 

1 9nn*A 
izuu  0 

•1901 

4ft9 

40Z 

00 

ACi'^ 

4:U  0 

9ft7*1 

1  901 '0 
IZUl  u 

•1  ^14 

1014 

474 
4  <  4 

00 

41  ^q 

9ftC*9 
Zoo  z 

1  901 ^q 
IZUl  0 

•1  ^qA 

lOOD 

4AA 
4DO 

0/ 

A9'q 

4:ii  0 

9ftQ'q 

ZoH  0 

1 9m  '7 

1  ZUl  / 

•1  ^A4 
loD4 

4Kft 
400 

oo 

40  0 

Zc/U  4 

1  909*0 

•1  ^ftO 
lOoU 

4/i1 

401 

Oa 

44  0 

9Q1  'A 

1 909*4. 

IZUZ  4 

±4UO 

444 
'I'll 

40  0 

9Q9*7 
ZtrZ  4 

1 909*7 

1 ZUZ  1 

•14-9,^ 

4^7 
40  i 

til 
Dl 

4D  0 

9Qq*ft 

Z«70  0  • 

1 9r^^*i 

i  ZUo  1 

•1447 
±44 1 

4^0 
40 1/ 

4/  0 

9Qd*ft 

Zy4  0 

1  90'^ 'A 

J  ZUO  4 

•1 4AQ 

494 

Do 

Aft*q 

4o  0 

Zf^O  1/ 

1  90^*7 

J  ZUo  1 

•140^ 

417 

04 

4c>  0 

9QA*Q 

zyo  a 

1  90/1*0 
1  ZU4  U 

•1,^1  A 

411 

rrl  1 

00 

ou  0 

9Qft'n 
zyo  u 

I904.*q 

1ZU4  0 

J.tJOO 

AA 
DO 

'^i  'q 
01  0 

1  904.*A 

iZU4  0 

•1/^AO 

399 

A7 

0^  0 

^nn*n 

1  904. '0 

±ZU4  u 

•l/^ft^ 

±000 

Aft 

Oo  0 

1 90K*9 

A  ZUO  Z 

•1 AO.^ 

388 

AQ 

04  0 

qr»i  '0 
oui  y 

1 90K*'=; 
±zuo  0 

•1 A97 

383 

7n 
/u 

00  0 

OUZ  a 

1 90'=J*ft 

•1  A4ft 

378 

71 
/ 1 

00  0 

^^nq*o 

OUO  t7 

1  90A*1 

IZUQ  1 

•1 A70 

373 

79 

^7*q 
0/  0 

qnzL'ft 

oU4  0 

1 90A*^ 

±ZUO  0 

•1 AQ9 

368 

7Q 

f=ift'q 
Oo  0 

oUO  / 

1 90A*A 

±ZUD  D 

•1714 

1 1  14 

363 

7zL 

Oa  0 

qnA*A 

oUO  0 

1 90A*0 

IZUD  tJ 

•17^A 

359 

7c: 

AH'Q 

oU  0 

oU/  0 

1 907*9 
IZU/  Z 

•1 7*^0 

1 1  Ou 

000 

7A 

A1  ^q 

qnft'A 
oUo  4 

1 907*4 
IZU 1  4 

*17ft9 
1 1  oz 

349 

77 

A9«Q 

0Ui7  0 

1 907*7 
IZU/  / 

•1ft04 

lc5U4 

Ort<J 

78 

63-3 

310-2 

1208-0 

•1826 

341 

79 

64*3 

311*1 

I2O8-3 

-1848 

DOT 

oo7 

80 

65-3 

312-0 

1208-5 

-1869 

333 

81 

66-3 

312*8 

1208-8 

•1891 

329 

82 

67-3 

313-6 

1209-1 

-1913 

325 

83 

68-3 

314-5 

1209*4 

•1935 

321 

THE   engineer's    HANDY-BOOK.  83 


TABLE  —  ( Continued.) 


Total  Pressure 
per Square  Inch 
measured  from 
a  Vacuum. 

Pressure 
above  At- 
mosphere. 

Sensible 
Temperature 
in  Fahren- 
heit degrees. 

XOIdl  Xlcaii  111 

Degrees  from 
Zero  of  Fah- 
renheit, 

w  eign  L  oi 
one  Cubic 
Foot  of 
Steam. 

Relative  Volume 

of  Steam  com- 
pared with  Water 
from  which  it 
was  raised. 

84 

69-3 

315-3 

1209-6 

•1957 

318 

85 

70-3 

316-1 

1209-9 

-1980 

314 

86 

71-3 

316-9 

1210-1 

*2002 

311 

87 

72-3 

317-8 

1210-4 

*2024 

308 

88 

73-3 

318-6 

1210-6 

*2044 

305 

89 

74-3 

319-4 

1210-9 

•2067 

301 

90 

75-3 

320-2 

1211-1 

•2089 

298 

91 

76-3 

321-0 

1211-3 

•2111 

295 

92 

77-3 

321-7 

1211-5 

•2133 

292 

93 

78-3 

322-5 

1211-8 

•2155 

289 

94 

79-3 

323-3 

1212-0 

•2176 

286 

95 

80-3 

324-1 

1212-3 

•2198 

283 

96 

81-3 

324-8 

1212-5 

•2219 

281 

97 

82-3 

325-6 

1212-8 

•2241 

278 

98 

83-3 

326-3 

1213-0 

•2263 

275 

99 

84-3 

327-1 

1213-2 

•2285 

272 

100 

85-3 

327-9 

1213-4 

•2307 

270 

101 

86-3 

328-5 

1213-6 

•2329 

267 

102 

87-3 

329-1 

1213-8 

•2351 

265 

103 

88-3 

329-9 

1214-0 

•2373 

•262 

104 

89-3 

-  330-6 

1214-2 

•2393 

260 

105 

90-3 

331-3 

1214-4 

•2414 

257 

106 

91-3 

381-9 

1214-6 

•2435 

255 

107 

92-3 

332-6 

1214-8 

•2456 

253 

108 

93-3 

333-3 

1215-0 

•2477 

251 

109 

94-3 

334-0 

1215-^ 

•2499 

249 

110 

95-3 

334-6 

1215-5 

•2521 

247 

96-3 

335-3 

1215-7 

•2543 

245 

m 

97-3 

336-0 

1215-9 

•2564 

243 

113 

98-3 

336-7 

1216-1 

•2586 

241 

114 

99*3 

337-4 

1216-3 

•2607 

239 

115 

100*3 

338-0 

1216-5 

•2628 

237 

116 

101*3 

338-6 

1216-7 

•2649 

235 

117 

102*3 

339-3 

1216-9 

•2674 

233 

118 

103-3 

339-9 

1217-1 

•2696 

231 

119 

104*3 

340-5 

1217-3 

•2738 

229 

120 

105-3 

341-1 

1217-4 

•2759 

227 

121 

106-3 

341-8 

1217-6 

-2780 

225 

122 

107-3 

342-4 

1217-8 

•2801 

224 

123 

108-3 

348-0 

1218-(l 

•2822 

ooo 

124 

109-3 

343-6 

1218-2 

•2845 

221 

125 

110-3 

344-2 

1218-4 

•2867 

219 

126 

111-3 

344-8 

1218-6 

•2889 

217 

127 

112*3 

345-4 

1218-8 

•2911 

215 

84  THE   ENGINEER'S  HANBY-BOOK. 


TABLE  —  ( Concluded,) 


Total  Pressure 
per  Square  Inch 
measured  from 
a  Vacuum. 

Pressure 
above  At- 
mosphere. 

Sensible 
Temperature 
in  Fahren- 
heit degrees. 

Total  Heat  in 
Degrees  from 
Zero  of  Fah- 
renheit. 

Weight  of 
one  Cubic 
Foot  of 
Steam. 

Relative  Volume 

of  Steam  com- 
pared with  Water 
from  which  it 
was  raised. 

1  QC 

llO  D 

O40  U 

1  91  Q«Q 

izio  y 

•OQQQ 

zyoo 

Z14 

1  9Q 

1 1  A»Q 
114  O 

O40  0 

1  91  Q'1 

iziy  1 

zyoo 

01 0 
ZlZ 

1  Qn 
loU 

llO  O 

QA7*9 
o4/  Zi 

1  91  Q  •  Q 

iziy  o 

•0Q77 

zy/  / 

01 1 

Zll 

1  Q1 

llo  O 

QA7«ft 
04i  O 

1  91  Q.c: 

iziy  o 

.  OQQQ 

zyyy 

zuy 

1  Q9 

11  /  O 

o4o  O 

1  91  Q'A 

iziy  0 

oUZU 

OAQ 

Zl)o 

loo 

llo  O 

o4o  y 

1  91  Q'Q 

iziy  o 

•QA  1A 
oU4U 

OAA 

zuo 

1  QJ. 

iiy  o 

o4y  O 

1 99A«A 

oUOU 

OAc: 
ZUO 

loo 

1  9A*Q 
IZU  O 

OOU  1 

1 99A-9 

•QAGA 
oUoU 

OAO 

ZUo 

1  Qft 
loD 

1  91  "Q 
IZl  o 

oOU  0 

1 99A  •  Q 
IZZU  o 

•Q1  A1 
OlUl 

OAO 

ZUZ 

1  Q7 

1  99'Q 
IZZ  o 

Q=;i  '9 

oOl  Zi 

1 99a • ^ 

•Q1  01 

olZl 

OAA 

ZUU 

loo 

1  9Q'Q 
^IZo  O 

OOl  O 

1 99a  •7 

•Q1  /lO 
ol4Z 

1  QA 

lyy 

lOtf 

1  9A»Q 
1Z4  O 

OOZ  4 

1 99A«Q 

izzu  y 

olOZ 

1  QQ 

ly© 

14:U 

1  9c:'Q 
i  ZO  O 

ooz  y 

1  991  'A 

•Q1  QA 
olo4 

1  Q7 

jyy 

141 

1  9A'Q 
IZO  O 

oOo  O 

1  001 '9 

IzZl  Z 

•QOAA 
oZUO 

1  Qc: 

lyo 

14Z 

1  97 'Q 
IZ/  O 

OOl  U 

1  OOl  '^l 

IZZl  4 

•QOOQ 
oZZo 

1  QA 

iy4 

14:0 

1  9Q'Q 

IZo  O 

OOi  0 

1 OOl  "A 

IZZl  0 

oZOo 

1  QQ 

lyo 

144 

1  9Q  •  Q 

izy  o 

OOO  u 

1  OOl •7 

IZZl  i 

•Q07Q 
oZ/o 

1  QO 

lyz 

140 

1  QA*Q 
loU  O 

oOO  0 

1  OOl  'Q 

izzi  y 

•QOQA 

ozy4 

IQA 

lyu 

1 AA 
140 

1  Q1  'Q 
lol  O 

oOO  1 

1 OOO 'A 

IZZZ  u 

ocSiO 

1  QQ 

loy 

1 A7 
14/ 

1  Q9'Q 
loZ  O 

oOO  / 

1 OOO'O 

oooO 

1  QQ 
J  00 

1  AQ 
14o 

1  QQ«Q 
loo  O 

OO/  Z 

T  Oi>O.Q 

IZZZ  o 

.QQC:7 
ooO/ 

1  Q7 

lot 

1  AQ 
14y 

1  QA'Q 
lo4  o 

OO/  o 

IZZZ  o 

.0077 
00/  / 

1  QA 

loO 

lOU 

loo  o 

oOo  O 

1  QA 

lo4 

loo 

1  /I  A«Q 

14U  o 

QA1  'A 

obl  U 

IZZo  0 

ooUU 

1  7A 

1  /y 

1  AA 

IbO 

140  o 

oOo  4 

1 00 A • 0 

1ZZ4  Z 

•QAA7 

oOU/ 

1  7/1 
1/4 

loo 

1  t^A'Q 

loU  O 

oOO-^U 

1  OO/l  -Q 

1ZZ4  'J 

.071  /I 

0/ 14 

1  AQ 

loy 

1  7A 
1  i\J 

loo  o 

oOo  Z 

1  OOCC«7 

IZZo  / 

•QQOI 
ooZl 

1  A/1 

104 

1  7cr 
1  /  0 

1  AA'Q 

iOU  o 

o/U  o 

1 OOA* 1 

IZZO  4 

•QQOQ 
oVJZo 

1  c^Q 

loy 

1  Q.(\ 
loU 

lOO  o 

Q79«Q 

oiA  y 

1 007  •  1 
IZZ/  1 

4UoO 

loo 

loO 

1  7A«Q 
1  /U  o 

O/O  O 

1 007 'Q 
IZZ/  0 

•A1 40 

41 4Z 

1  til 

lol 

1  OA 

lyu 

1  /O  O 

Q77- 
O/  /  O 

1  OOC*'^ 

IZZo  0 

4Z0U 

14o 

lyo 

1  QA'Q 
loU  O 

Q7Q«7 

o/y  / 

1 000 'O 
IZZV;  Z 

4oO/ 

1 AA 
144 

9AA 

loo  O 

QQ1  "7 

ool  / 

1  OOQ  •  Q  - 

j  zzy  0 

•AAA/1 
4404 

1 A1 
141 

91 A 

ziu 

lyo  o 

QQt? 'A 

ooO  U 

1 0Q1  'I 

IZol  1 

•AAAQ 
400o 

1  Qc; 
loO 

99A 

ZUO  o 

ooy  y 

1 OQO'Q 
IZoZ  0 

•AQ70 
4o<  Z 

1  OQ 

izy 

9'^A 
ZoU 

91  c:«Q 

Zlo  O 

oyd  o 

IZoo  0 

OU/Z 

1  OQ 
IZo 

9/1 A 
Z4U 

ZZO  O 

oy/  o 

1  OQ  4 'A 

lZo4  0 

OZ/U 

1 1 Q 

iiy 

250 

235-3 

401-1 

1235-7 

-5471 

114 

260 

245-3 

404-5 

1236-8 

-5670 

110 

270 

255-3 

407-9 

1237-8 

-5871 

106 

280 

265-3 

411-2 

1238-8 

-6070 

102 

290 

275-3 

414-4 

1239-8 

•6268 

99  1 

300 

285-3 

417-5 

1240-7 

•6469 

96  ! 

THE   engineer's    HANDY-BOOK.  85 


TABLE 

SHOWING  THE  STEAM  PRESSURE  IN  POUNDS  PER  GAUGE  ;  THE  ABSOLUTE 
PRESSURE  IN  POUNDS  AND  INCHES  OF  MERCURY;  THE  TEMPERATURE; 
THE  TOTAL  HEAT  IN  STEAM  PER  POUND  ;  THE  LATENT  HEAT  PER  POUND; 
THE  HEAT  OF  THE  WATER;  THE  RELATIVE  VOLUME,  AND  WEIGHT  OF 
STEAM  PER  CUBIC  FOOT,  FOR  VARIOUS  PRESSURES  * 


Pressure 

per 
Gauge. 

Total 
lbs. 

Inches  of 
Mercury. 

Temper- 
ature, 
Fah. 

Total  Heat 
per  lb. 

Latent 
Heat 
per  lb. 

Heat  in 
Water 
per  lb. 

Relative 
Volume. 

Weight 

per 
Cub.  Ft. 

1 

2036 

102* 

1145  05 

102*08 

17983* 

'00347 

2 

4*072 

126*27 

1152*45 

102601 

126*44 

10353* 

•00602 

3 

6*108 

141  62 

115713 

1015*25 

141*87 

7283*8 

•00856 

4 

8*144 

153-07 

1162*62 

1007*23 

153*39 

5608*4 

'01112 

5 

10*180 

162*33 

1163*45 

1000-7^ 

162*72 

4565*6 

■01366 

12*216 

170*12 

1165*83 

995*25 

170*57 

3851-0 

'01619 

7 

14*252 

176*91 

1167*89 

990*47 

177*42 

3330*8 

'01837 

16*288 

182*91 

1169*72 

986*24 

183*48 

2935*1 

'02125 

9 

18  324 

188'32 

117137 

982*43 

188*94 

2624*1 

'02377 

10 

20*360 

193*24 

1172-87 

978*96 

193*92 

2373*0 

'02628 

11 

22*396 

197*77 

1174*26 

975*76 
972*80 

198*49 

21663 

'02880 

12 

24*432 

201*96 

1175*53 

202*74 

19930 

'03130 

13 

26*468 

205*88 

1176*73 

970-02 

206*71 

1845*7 

'03380 

14 

28*504 

209*56 

117785 

967  43 

210*43 

1718*9 

'03629 

'304 

15 

30*540 

213  02 

1178*91 

964  97 

213*94 

1608*6 

'03878 

1'304 

16 

32*576 

216*30 

1179*91 

962*66 

217*25 

1511*7 

'04123 

2-304 

17 

34*612 

219*41 

1180*86 

960*45 

220*41 

1426*2 

'04374 

3' 304 

18 

36*648 

222*38 

118176 

958*34 

223*42 

11^9*8 

'04622 

4"304 

19 

38*684 

225 "20 

1182*63 

956*34 

226*28 

1281 -1 

•04868 

5-304 

20 

40*720 

227*92 

1183-45 

954*41 

229*04 

1219*7 

'05119 

6  "304 

21 

42756 

230*51 

1184*25 

952*57 

231*67 

1163*8 

7*304 

22 

44*792 

233*02 

1185*01 

950*79 

234*22 

1112*9 

* 05605 

8' 304 

23 

46*8*28 

235*43 

1185*74 

949*07 

236*67 

1066*3 

"05851 

9*304 

24 

48*864 

237*75 

1186*45 

947*4*2 

239-03 

1023*6 

'06095 

10*304 

25 

50*900 

240*00 

1187*14 

945*82 

241*31 

984*23 

'06338 

11*304 

26 

52*936 

242*17 

1187*80 

944*28 

243*59 

947*86 

'06582 

12*304 

27 

54*972 

244**28 

1188*44 

942*77 

94=^-A7 
Z-40  D/ 

914*14 

'068*^4 

13*304 

28 

57*008 

246*33 

1189*07 

941*32 

9A7'7t 
Z-±  1  /  0 

889-80 

'07067 

14*304 

29 

59*044 

248*31 

1189*67 

C^Q.fiO 
0)0  uv  . 

'07308 

15*304 

30 

61*080 

250*24 

1190*26 

voo 

251*74 

8*^6*3'^ 

*0/o50 

16*304 

31 

63*116 

259'i2 

ij  yu  oo 

ZOO  04 

800*79 

'07791 

17*304 

32 

65*152 

253  95 

1191*40 

935*88 

zoo  oz 

766*83 

•nsA^i 
uouoi 

18*304 

33 

67*188 

255*73 

1191*94 

934-61 

257*33 

754*31 

*08271 

19*304 

34 

69*224 

257-46 

1192-47 

933-36 

259*11 

733*09 

'08-510 

20*304 

35 

71*260 

•259*17 

1192-99 

932*15 

260*84 

713*08 

'08749 

21*304 

36 

73*296 

260*83 

1193*49 

930*96 

262*53 

694-17 

'08987 

22*304 

37 

75*331 

262*46 

1193*99 

929*81 

2W-18 

676-27 

'09*2*25 

23-304 

38 

77*367 

264-04 

1194-47 

.  928*67 

265*80 

659*31 

*09462 

24*304 

39 

79*403 

265*60 

1194*94 

927*56 

267-38 

643*21 

*09700 

25*304 

40 

81*439 

267*12 

1195-41 

926-47 

268-94 

627*91 

*09936 

26*304 

41 

83-475 

268-61 

1195*86 

9*25-40 

270*46 

613*34 

*10172 

27*304 

42 

85*511 

270-07 

1196*31 

9*24*36 

271-95 

59946 

•10407 

28*304 

43 

87*547 

271*51 

1196*75 

923-33 

273*42 

586-23 

'10(U2 

29*304 

44 

89*583 

272*91 

1197*18 

9*22*32 

274*86 

573-5S 

•10877 

30*304 

45 

91*619 

274*29 

1197-60 

921-33 

276*27 

561*50 

•11111 

31*304 

46 

93*655 

275*65 

1198-01 

920-36 

277*65 

04994 

•11344 

32*304 

47 

95*691 

276*99 

1198*42 

919*40 

279*02 

538*87 

•11577 

1  33*304 

48 

97*727 

278-30 

1198-82 

918*47 

280*35 

5*28*25 

•11810 

I  34-304 

49 

99-763 

279-58 

1199-21 

917*54 

281*67 

518*07 

•12042 

1  35*304 

50 

101*799 

280-85 

1199-60 

916*63 

282*97 

508*29 

•12273 

*  John  W.  Hill. 


8 


86 


THE   engineer's  HANDY-BOOKo 


TABLE 

SHOWING  THE  STEAM  PRESSURE  IN  POUNDS  PER  GAUGE;  THE  ABSOLUTE 
PRESSURE  IN  POUNDS  AND  INCHES  OF  MERCURY;  THE  TEMPERATURE; 
THE  TOTAL  HEAT  IN  STEAM  PER  POUND  ;  THE  LATENT  HEAT  PER  POUND; 
THE  HEAT  OF  THE  WATER;  THE  RELATIVE  VOLUME,  AND  WEIGHT  OF 
STEAM  PER  CUBIC  FOOT,  FOR  VARIOUS  PRESSURES. 


.'  Pressure 
per 
Gauge. 

Total 
lbs. 

Inches  of 
Mercury, 

Temper- 
ature, 
Fah. 

Total  Heat 
per  lb. 

Latent 
Heat 
per  lb. 

■ 

Heat  in 
Water 
per  lb. 

Relative 
Volume. 

Weight 

per 
Cub.  Ft. 

36 '304 

51 

103  84 

282' 10 

1198*98 

915-74 

284*24 

498*89 

'12505 

37  "304 

52 

105 '87 

283*32 

1200*35 

914-86 

285*50 

489*85 

-12736 

38"  304 

53 

107*91 

284*53 

1200*72 

913*99 

286*73 

481*15 

'12966 

39' 304 

54 

109*94 

285*72 

1201*08 

913*13 

-287*95 

472*77 

'13196 

40  304 

55 

11198 

286*89 

1201*44 

912*29 

289*15 

464*69 

'13428 

41'304 

56 

114*02 

288*05 

1201*80 

911*46 

290*34 

456*90 

"13652 

42  304 

57 

116*05 

289*11 

1202*14 

910*64 

291*50 

449*38 

-13883 

43  304 

58 

118*09 

290*32 

1202*49 

909*83 

292*65 

442*12 

•14111 

44'304 

59 

120*12 

291*42 

1202*82 

909*03 

293*79 

435*10 

•14338 

45*304 

60 

122*16 

292*52 

1203-16 

908-25 

294*91 

428*32 

•14566 

46 '304 

61 

124*19 

293*60 

1203-49 

907-47 

296  02 

421*75 

•14792 

47 '304 

62 

126*23 

294*66 

1203-81 

906*70 

297*11 

415*40 

•15018 

48' 304 

63 

128*27 

295*71 

1204-13 

905*95 

298*18 

409*25 

•15244 

49 '304 

64 

130*30 

296*75 

1204-45 

905*20 

299 "25 

403*29 

•15469 

50 '304 

65 

132*34 

297-78 

1204-76 

904*46 

300' 30 

397-51 

•15694 

51 '304 

66 

134*37 

298' 79 

1205-07 

903-73 

301*34 

391*90 

•15919 

52' 304 

67 

136*41 

299*79 

1205-38 

903*01 

302*37 

386*47 

•16130 

53-304 

68 

138*45 

300*77 

1205*68 

902*30 

303*38 

381*18 

"16366 

54  304 

69 

140*48 

301*75 

1205*97 

901*60 

304*37 

376*06 

•16590 

55*304 

70 

142*52 

302*72 

1206'27 

900  90 

305*37 

371*07 

•16812 

56 '304 

71 

144*55 

303*67 

1206 -56 

900*21 

306 -35 

366*24 

"17035 

57  304 

72 

146*59 

304*62 

Xiiuu  00 

899*53 

307*32 

361 -53 

•17256 

58  304 

73 

148*63 

305*55 

1207*13 

898*85 

308*28 

356*95 

"17478 

59*304 

74 

150"  66 

306*47 

1207-4'2 

898*19 

309*23 

352*49 

"17690 

60*304 

75 

152*70 

307*39 

1207*69  * 

897*53 

310*16 

348*15 

-17919 

6]  *304 

76 

154*73 

308*29 

1207*97 

896*88 

311*09 

343*93 

•18139 

62*304 

77 

156*77 

309*18 

l'^08*24 

896*23 

312-01 

339*81 

'18359 

63*304 

78 

158*81 

310*07 

1*208*51 

cgr;.r,q 
OuO  ov 

312*92 

335*81 

•18578 

64*304 

79 

160*84 

310*94 

1208*78 

894*95 

313*82 

331*89 

"18797 

65*304 

80 

162*88 

311*81 

1209*04 

894*33 

314*71 

328*08 

"19015 

66*304 

81 

164*91 

312*67 

1209*30 

893*71 

315*59 

324*37 

"19233 

67*304 

82 

166-95 

313*52 

1209*56 

893-09 

316-47 

320*74 

"19451 

68-304 

83 

168*99 

314*36 

1209-82 

892-49 

317*33 

317*20 

•19668 

69*304 

84 

17102 

31519 

1210*07 

891*88 

318*19 

313*74 

•19885 

70-304 

85 

173*06 

316-02 

1210*33 

891-29 

31904 

310-36 

•20101 

71-304 

86 

175-09 

316*84 

1210*58 

890*69 

319*89 

307*07 

•20317 

72-304 

87 

177*13 

317-65 

1210*83 

89011 

320*72 

303*85 

"20532 

73*304 

88 

179*17 

318-45 

1211*07 

889*52 

321-54 

300*70 

•20747 

74-304 

89 

181-20 

319'25 

1211*31 

888*95 

322*36 

297-62 

•20962 

75-304 

90 

185*24 

320  04 

1211*55 

888*38 

323-17 

294*61 

•21185 

76-304 

91 

185*27 

320-82 

1211*79 

887*81 

323*»8 

291*66 

•21390 

77-304 

92 

187*31 

321-58 

1212-03 

887*25 

324*78 

288*78 

•21603 

78-304 

93 

189-35 

322*36 

1212-26 

886*69 

325*57 

285*96 

•21816 

79*304 

94 

191*38 

323*13 

1212*49 

886-13 

326*36 

283*21 

"22029 

80*304 

95 

193*42 

323*88 

1212-72 

885*59 

327*13 

280-50 

•22241 

81*304 

96 

195-45 

324-63 

1212*95 

885*04 

327*91 

277*86 

"22453 

82*304 

97 

197*49 

325*38 

1213-18 

884*50 

328*68 

275*27 

"22675 

83*304 

98 

199*53 

326*11 

1213*40 

.883*97 

329*43 

272*73 

•22873 

84-304 

99 

201*56 

326-84 

1213*63 

883  44 

330*19 

270*24 

•23085 

85-304 

100 

203*60 

327-57 

1213-85 

882*91 

330*94 

267*80 

•23296 

THE   engineer's  HANDY-BOOK. 


87 


TABLE 

SHOWING  THE  STEAM  PRESSURE  IN  POUNDS  PER  GAUGE  ;  THE  ABSOLUTE 
PRESSURE  IN  POUNDS  AND  INCHES  OF  MERCURY;  THE  TEMPERATURE ; 
THE  TOTAL  HEAT  IN  STEAM  PER  POUND  ;  THE  LATENT  HEAT  PER  POUND ; 
THE  HEAT  OF  THE  WATER;  THE  RELATIVE  VOLUME  AND  WEIGHT  OF 
STEAM  PER  CUBIC  FOOT,  FOR  VARIOUS  PRESSURES. 


Pressure 

per 
Gauge. 

Total 
lbs. 

Inches  of 
Mercury. 

Temper- 
ature, 
Fah. 

Total  Heat 
per  lb. 

Latent 
ft  cat 

per  lb. 

Heat  in 
Water 
per  lb. 

Relative 
Volume. 

Weight 

per 
Cub.  Ft. 

86*304 

101 

205*64 

328*29 

1214*07 

882*39 

331*68 

26o*81 

'23505 

87*304 

102 

207*67 

329*00 

1214*28 

881*87 

332*41 

263*07 

"23715 

88  oU4 

103 

*209*71 

329*71 

1214*50 

881*35 

333*15 

260*77 

'23924 

89*304 

104 

211*74 

330*42 

1214*71 

880  85 

333*86 

258*52 

'24132 

90*304 

105 

213*78 

331*11 

1214*93 

880*34 

334*59 

256*31 

'24340 

91*304 

106 

215*82 

331*80 

1215*14 

879*84 

335*30 

254*14 

'24548 

92*304 

107 

217*85 

33249 

1215*35 

879*34 

336*01 

25201 

* 24 756 

93*304 

108 

21989 

333*  17 

1215*55 

878*84 

336*71 

249*92 

* 24 963 

94*304 

109 

221*92 

333*85 

1215*76 

878-35 

337*41 

247*87 

25169 

95*304 

110 

223*96 

334*52 

1215*97 

877*86 

338*11 

245*86 

* 25375 

96*304 

111 

225*99 

335*19 

1216*17 

877*38 

338*79 

243*88 

*25581 

97*304 

112 

228-03 

335 '85 

1216*38 

876  90 

339*48 

241*94 

*25786 

98*304 

113 

230  07 

336*51 

1216*58 

876  42 

340*16 

240*03 

'25991 

99*304 

114 

232*10 

337*16 

1216*77 

875*94 

340*83 

238*15 

.  '26204 

lUU  oU4 

115 

234*14 

337*81 

1216  97 

875*47 

341*50 

236*31 

'26400 

101*304 

116 

236*17 

338*46 

1217*17 

875  00 

342*17 

234*50 

'26611 

102*304 

117 

238*21 

339  10 

1217*36 

874*54 

342*83 

232*70 

*26816 

103*304 

118 

240*25 

66\)  16 

1217*56 

874*07 

343*49 

231*00 

'270'20 

104*304 

119 

242*28 

.340*37 

1217*75 

873*61 

344*14 

229-30 

*27224 

105*304 

120 

244*32 

340*99 

1*217*94 

873*15 

344*79 

227*56 

•27421 

lUo  o04 

121 

246*35 

341*62 

121813 

872*70 

345*43 

226*00 

*27628 

1U7  o04 

122 

248*39 

342*24 

1218*32 

872*25 

346*07 

224*40 

'27828 

iU8  o04 

123 

250*43 

342*85 

1218*51 

871*80 

346*71 

222*80 

'28027 

109  oU4 

124 

252*46 

343*46 

121 869 

871*35 

347*34 

221  20 

'28227 

110*304 

125 

254*50 

344*07 

1218*88 

870*91 

347*97 

219*50 

'28422 

111*304 

126 

256*54 

344*68 

1219*07 

870*47 

348*60 

218*20 

'28625 

112*304 

127 

258*57 

34528 

1219**25 

870*03 

349**22 

216*70 

•28824 

113*304 

128 

260*61 

345-87 

1219-43 

809 '60 

349*83 

215**20 

'29023 

114*304 

129 

262  64 

346*46 

1*219*61 

869*  16 

350*45 

213-70 

'29*2*22 

115*304 

130 

264*68 

347*06 

1219*79 

868 74 

1^1*06 

212*07 

•29419 

116*304 

131 

266*72 

347*64 

121997 

868-31 

351*66 

210*90 

•29618 

117*304 

132 

268-75 

348*23 

122015 

867*88 

352'27 

20950 

•29816 

118*304 

133 

270*79 

348*80 

1220  32 

867*46 

352*86 

208*10 

•30013 

119*304 

134 

272*82 

349*38 

1220*50 

86704 

353*46 

206*70 

'30*209 

120*304 

135 

274*86 

349*95 

1220*67 

866*62 

354*05 

205*18 

'30406 

121*30  \ 

136 

276*89 

350*52 

1220*85 

866*21 

354*64 

204*10 

'30601 

122*304 

137 

278*93 

351*09 

12*2102 

865*79. 

355*23 

202*80 

-30796 

123-304 

138 

280*96 

351*75 

1221*19 

865*38 

355*81 

201*50 

'30990 

124*304 

139 

283*00 

352*21 

1221*36 

8^*97 

356*39 

2av*2^) 

•31186 

1*25*304 

140 

'>8;3*04 

352*76 

1221*53 

864*56 

356*97 

198*78 

'31385 

126*304 

141 

287*07 

353*32 

1221*70 

864*16 

357*54 

197*80 

'31586 

127-304 

142' 

289*11 

353  87 

1221*87 

86376 

358*11 

196*60 

•31788 

1*28*304 

143 

291*15 

354*42 

1222*04 

863*36 

358*67 

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'31990 

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293*18 

354*96 

12*22  20 

862-96 

359*24 

194*20 

•32190 

130*304 

145 

295*22 

355*50 

12*22*37 

mi-bi 

359*80 

192*83 

'3*2354 

131*304 

146 

•297*25 

356*04 

12*22*53 

862*17 

360*36 

191*90 

'32592 

132*304 

14V 

299*29 

356*57 

1 '2*22*69 

861*78 

360*91 

190*80 

•32794 

133*304 

148 

301*33 

357  10 

12*22*85 

861*39 

361*46 

189*70 

'32995 

134*304 

149 

303*36 

3^57*63 

1*223*02 

861*01 

36201 

188*60 

33196 

135*304 

150 

305*40 

358*16 

1223*18 

86062 

362*56 

187*26 

'33315  , 

88 


THE   engineer's  HANDY-BOOK. 


The  Brown  Automatic  Cut-Olf  Steam-Engine. 

The  cuts  on  pages  89,  90,  represent  the  Brown  Automatic 
Cut-off  High-pressure  Engine. — The  housing,  which,  as  wilJ  be 
observed,  is  of  the  girder-frame  pattern,  somewhat  resembles  the 
Corliss,  though  the  engine  is  different  in  every  other  respect.  The 
cylinder,  which  contains  the  steam-  and  exhaust-ports,  is  encased 
in  an  ornamental  cast-iron » jacket,  and  rests  on  a  square,  tapering 
column  which  extends  nearly  the  full  length.  By  a  judicious  dis- 
tribution of  the  materials,  every  part  possesses  sufficient  rigidity, 
without  extra  weight  of  metal.  In  its  design,  the  evils  induced  by 
expansion,  and  the  liability  to  get  out  of  line,  have  been  scientifi- 
cally considered  and  practically  obviated.  A  spur-gear  on  the 
main  shaft  gives  motion  to  a  shaft  parallel  with  and  below  the 
axis  of  the  cylinder.  Froin  this  shaft  the  motions  of  the  valves 
are  derived. 

There  are  four  valves,  one  steam  and  one  exhaust  at  each  end 
of  the  cylinder,  which  are  independent,  and  though  slide-valves,  as 
they  have  but  one  function  to  perform  for  each  revolution,  i,  e., 
admitting  or  exhausting  the  steam,  they  are  necessarily  of  a  dif- 
ferent construction  from  the  ordinary  slide-valve.  The  exhaust- 
valves  are  horizontal,  and  travel  at  right  angles  with  the  cylinder ; 
the  motion  being  derived  from  cams  on  the  longitudinal  shaft, 
which  is  positive  in  both  directions.  The  shape  of  the  camways 
is  such  that  the  motions  of  the  valves  in  opening  and  closing  are 
very  quick,  and  allow  of  their  remaining  stationary  during  nearly 
the  whole  stroke  of  the  piston,  thus  insuring  a  perfectly  free  ex- 
haust, and  preventing  any  possibility  of  back  pressure. 

The  steam-valves,  which  are  vertical,  are  of  the  gridiron  pat- 
tern, and  require  very  little  movement  to  give  a  full  port  opening. 
They  are  operated  by  eccentrics  on  the  cam-shaft,  in  connection 
with  the  following  device  for  regulating  the  point  of  cut-off.  A 
vibrating  lifter,  having  the  fixed  centre  at  its  outer  end,  is  con- 
nected, at  about  the  middle  of  its  length,  with  the  eccentric-rod ; 
while  the  inner  end  engages  a  spring-catch  or  projection  on  the 


THE   ENGINEER\s  HANDY-BOOK. 


91 


valve-stem,  giving  to  the  valve  a  positive  motion  on  the  left  or  up 
stroke,  and  allowing  of  its  being  tripped,  or  released  for  closing, 
when  the  point  of  cut-off  is  reached  — jar  being  prevented  by 
means  of  small  dash-pots.  On  the  spring-catch  of  the  valve- 
stems  is  an  inverted  wedge,  by  means  of  which  the  valves  are 
tripped. 

The  governor,  which,  as  will  be  observed,  is  enclosed  in  an  or- 
namental case  or  shell,  is  very  sensitive  and  admirably  adapted  to 
these  engines,  is  of  the  centrifugal  fly-ball  type,  receives  a  positive 
motion  from  the  cam-shaft,  by  means  of  bevel-gears,  and  causes  a 
rod  running  parallel  with  the  shaft  and  back  of  the  valve-stems 
to  oscillate.  On  this  rod  and  opposite  to  each  wedge  is  an  arm, 
which,  when  the  speed  increases,  is  moved  by  the  governor  towards 
the  wedge,  thus  drawing  the  catch  away  from  the  lifter  as  it  rises, 
and  allowing  the  valve  to  drop,  while  the  lifter  continues  its  mov- 
ment  to  the  end  of  the  stroke  and  return,  when  it  engages  the 
catch  as  before. 

Both  steam-  and  exhaust-valves  have  ample  openings,  which,  in 
connection  with  their  quick  motions,  entirely  obviate  the  evil  aris- 
ing from  wire-drawing  the  steam,  or  choking  the  exhaust,  thereby 
causing  back  pressure.  The  only  unbalanced  pressure  on  the 
valve  is  an  area  of  about  one  square  inch  on  the  top,  for  the  pur- 
pose of  aiding  in  closing  them  quickly.  As  an  evidence  of  the 
small  amount  of  friction  induced  in  the  working  of  the  valves  of 
these  machines,  the  ordinary  starting-bar  is  dispensed  with,  and  an 
eight-inch  hand-wheel  on  the  cam-shaft,  which  possesses  sufficient 
leverage  to  work  the  valve  by  hand,  substituted  in  its  place. 

The  valve-gear  is  a  most  ingenious  and  admirable  combinatioa 
of  mechanical  devices,  being  very  simple,  and  susceptible  of  easy, 
convenient,  and  accurate  adjustment.  Its  operation  may  be  ex- 
plained as  follows :  The  shaft,  A,  receives  its  motion  from  a  gear 
on  the  main  shaft,  which,  in  turn,  imparts  motion  to  the  gov- 
ernor, and  through  the  medium  of  the  frictional  device,  or  coup- 
ling C,  to  the  shaft  B,  on  which  the  eccentrics,  D,  are  located, 
the  ends  of  the  straps  of  which  are  connected  to  the  horizontal 


92 


THE   ENGINEER'S  HANDY-BOOK. 


arms,  E,  which  extend  into  th«  square  slot  provided  in  the  slide- 
spindle,  and  to  the  catch  of  the  tongue.  As  the  shaft,  B,  revolves, 
the  ends  of  the  arms,  E,  will  reciprocate  vertically  in  the  square 
slot,  the  valve-stem  being  attached  to  the  guide,  F,  in  the  slot  of 
which  the  tongue,  6r,  is  pivoted  by  the  pin  shown  in  the  guide. 
The  upper  end  of  thfs  tongue  has  a  projecting  catch  upon  it,  be- 
neath which  stands  the  end  of  the  arm,  E,  which  lifts  the  valve  for 
the  admission  of  the  steam,  and  holds  it  open  until  the  tongue  is 
tripped,  when  the  valve  closes,  the  movement  being  instantaneous, 
and  rendered  noiseless  by  means  of  an  air-cushion  dash-pot. 

The  governor-spindle  is  attached  to  the  end  of  an  arm  which  is 
fast  upon  a  rod,  which,  being  immediately  back  of  the  shaft  By  is 
not  seen  in  the  cut ;  upon  this  rod,  and  immediately  behind  the 
steam-valve  spindle-guide,  F,  is  an  arm  standing  vertically,  and 
carrying  the  horizontal  pin,  JET.  The  tongue  which  at  one  end 
acts  as  a  catch  to  the  eccentric  arm,  at  the  other  end  protrudes 
from  the  back  of  the  slide-spindle  guide,  and  stands  directly  be- 
neath the  pin,  H,  so  that  w^hen  the  arm,  E,  lifts  (through  the 
tongue-catch)  the  steam-valve,  the  latter  remains  open  until  the 
tail  of  the  catch,  G,  meets  with  the  pin,  JT,  which  trips  the  tongue 
and  closes  the  valve.  The  governor  controls  the  position  of  che 
pin,  H,  and  determines  the  point  of  cut-off.  The  discs,  J,  on  the 
shaft.  By  are  provided  with  cam-grooves,  into  which  a  friction- 
roller  on  the  rocker-arm,  Ky  extends,  the  upper  arm,  Ly  being  at- 
tached to  the  exhaust-valve  spindle.  To  compensate  for  the  cir- 
cular motion  of  the  arm  and  the  vertical  movement  of  the  valve- 
spindle,  the  connection  between  them  is  made  by  the  eye  of  the 
spindle,  containing  a  slot  in  which  is  fitted  a  sliding  die,  to  which 
the  pin  of  the  arm  is  fitted.  Any  change  of  load  on  the  engine 
is  instantaneously  shown  by  the  governor.  Nevertheless,  the 
valve-gear  is  complicated,  and  liable  to  wear  out  rapidly  and 
become  a  source  of  annoyance  and  expense. 


THE  engineer's  HANDY-BOOK. 


95 


The  Harris  Corliss  Steam-Engine. 

The  cuts  on  pages  93  and  94  represent  the  Harris  Corliss  En- 
gine, one  showing  the  crank  and  cross-head,  the  other  the  eccentric 
and  vaive  gear.  It  will  be  observed  that  the  general  design  is 
symmetrical  and  well  proportioned,  rigidity  and  strength  being 
introduced  principally  where  the  greatest  longitudinal  strain  oc- 
curs, viz.,  between  the  cylinder-flange  and  the  centre  of  the  fly- 
wheel shaft.  Between  these  points  the  frame,  which  is  in  one 
casting,  is  vertically  deep  and  strongly  ribbedf  thus  insuring 
greater  strength  and  stiffness  than  could  be  obtained  by  any  other 
distribution  of  the  same  amount  of  material.  The  cross-head 
guides  are  cast  with  the  frame.  The  main  pillow-block  is  of  an 
improved  design,  with  the  feet  well  spread  out;  and  the  cylinder 
and  exhaust-chest  rest  upon  supports  the  entire  wadth  of  the 
chest.  The  engines  are  only  slightly  elevated  above  the  floor, 
thus  allowing  the  attendant  to  reach  every  part  with  the  greatest 
ease.  The  cylinders  and  chests  are  neatly  lagged  in  black  walnut, 
or  other  wood. 

The  piston -packing  is  of  the  most  improved  kind,  and  Is  claimed 
to  remain  perfectly  steam-tight  under  all  circumstances.  It  is 
set  out  by  means  of  German  silver  spiral  springs,  which  obviate 
the  difficulty  arising  from  the  cylinder  becoming  worn  larger  at 
the  ends,  or  its  liability  to  become  cut  or  fluted,  in  consequence 
of  its  being  set  out  too  tight.  Besides,  the  piston-rod  is  retained 
exactly  in  the  centre  of  the  cylinder.  The  spring  plates  for  the 
packing-rings  are  made  of  bronze  metal,  consequently  they  are 
not  liable  to  corrode.  The  distance  used  for  the  packing-ring  be- 
tween the  piston  and  the  follower  is  so  small  that  it  leaves  a  large 
amount  of  the  junk-ring  for  a  bearing,  or  a  wearing  surface  on  the 
lower  side  of  the  cylinder  in  the  horizontal  engine,  which  reduces 
the  liability  to  cut.  The  design  and  arrangement  of  this  pack- 
ing afford  the  most  convenient  facilities  for  taking  it  out,  putting 
it  in,  or  for  adjustment.  The  operation  of  the  packing  is  as  fol- 
lows: When  steam  is  admitted  into  either  end  of  the  cylinder,  the 


96 


THE  ENGINEER'S  HANDY-BOOK. 


packing-ring  is  carried  by  the  steam  over  to  the  side  of  the  groove 
in  the  junk-ring,  making  a  joint  there,  and  allowing  the  steam  to 
pass  down  and  under  the  packing-ring,  thus  placing  it  in  equili- 
brium; then  all  that  is  required  is  a  very  light  spring  to  hold  the 
packing  in  contact  with  the  cylinder. 

There  are  four  valves — two  steam  and  two  exhaust.  The  steam- 
valves  are  located  on  the  top  of  the  cylinder  at  each  end,  and 
open  directly  into  the  clearance,  which  obviates  the  waste  induced 
by  the  use  of  long  passages.  The  exhaust-valves  are  placed  in 
the  exhaust-che§t  on  the  lower  side  of  the  cylinder,  and,  as  in  the 
case  of  the  steam-valves,  open  into  the  clearance  spaces,  which  ar- 
rangement facilitates  the  escape  of  the  water  of  condensation  from 
the  cylinder,  and  obviates  the  liability  to  accident.  The  four 
valves  are  moved  by  one  eccentric  through  the  intervention  of  a 
wrist-plate ;  the  same  valves  admit  and  cut  off  the  steam. 

The  steam-valve  in  these  engines  commences  to  open  its  port  at 
one  end  of  the  cylinder  when  the  eccentric  is  producing  its  most 
rapid  movement,  and,  as  the  motion  of  the  eccentric  is  declining 
towards  the  end  of  the  throw,  an  increasing  speed  is  obtained  by 
means  of  the  wrist-plate,  which  compensates  for  the  slow  motion 
of  the  eccentric.  At  the  same  time  the  steam-valve  at  the  oppo- 
site end  of  the  cylinder  commences  to  lap  its  port  by  the  motion 
of  the  eccentric,  but  by  a  reverse  or  subtraction  of  speed  pro- 
duced by  the  same  wrist-plate,  which  speed  is  constantly  decreas- 
ing till  the  throw  of  the  eccentric  is  completed.  Or  in  other 
words,  the  lapping  and  opening  of  the  steam-ports  require  each  the 
same  amount  of  throw  of  the  eccentric,  producing,  for  instance,  a 
lap  of  i  an  inch  at  one  end  of  the  cylinder,  while  the  opposite 
end  has  an  opening  of  one  inch  and  one-eighth.  The  exhaust- 
valves  are  moved  by  the  same  eccentric  and  the  same  wrist-plate 
before  spoken  of,  but  they  have  a  much  greater  travel  for  the 
purpose  of  ridding  the  engine  of  the  exhaust  steam  easily  through 
the  exhaust-ports,  which  are  as  long  and  twice  as  wide  as  the 
steam-ports,  and  therefore  back  pressure  on  the  piston  of  the  en- 
gine is  avoided.    The  rapid  opening  and  slow  lapping  of  the  ex- 


THE   ENGINEER\s  HANDY-BOOK. 


97 


haust-ports  are  obtained  in  the  same  manner  as  in  tiie  case  of  the 
steam-ports,  but  much  faster,  as  the  travel  is  greater  on  the  open- 
ing of  the  exhaust  than  on  the  opening  of  the  steam-port,  in  order 
to  get  a  free  and  full  opening. 

The  variations  of  load  upon  these  engines  are  communicated 
to  the  steam-valves  instantly  by  the  governor,  the  valves  being 
moved  by  a  force  distinct  from  it,  yet  subjected  to  its  regulation. 
The  governor  in  no  case  performs  any  work,  and  only  indicates 
the  changes  required  to  the  levers  which  move  the  valves,  and 
needs  only  sufficient  force  to  move  a  small  stop.  Its  movement 
is  attended  with  the  least  possible  friction ;  the  stop  presents 
hardly  any  resistance  to  the  governor,  except  at  the  very  instant 
when  it  is  in  actual  contact  with  the  lever  constituting  its  fulcrum. 
This  momentary  resistance  by  the  bearing  of  the  lever  on  the 
stop  as  a  fulcrum  occupies  so  small  a  space  of  time  that,  com- 
pared with  the  period  during  which  the  governor  is  left  free  to 
move  the  stop,  it  is  practically  nothing.  As  a  precautionary 
measure,  a  safety  stop  is  connected  with  the  valve-gear,  so  that  in 
case  the  governor  should  become  inoperative,  and  should  fail  to 
act,  the  steam-valves  become  unhooked,  and  cannot  open,  and,  as 
a  universal  result,  the  engine  is  stopped,  although  the  valve  in  the 
steam-pipe  may  be  wide  open.  The  valves  are  circular,  and  oscil- 
late on  fixed  bearings  in  the  front  and  back  bonnets.  The  valve- 
stems  have  flat  blades,  which  extend  the  whole  length  of  the  valves 
in  the  steam-chest,  and  to  which  levers  are  keyed  for  the  purpose 
of  giving  them  motion.  The  valves  are  fitted  in  such  a  manner 
as  to^he  capable  of  adjusting  themselves  to  their  seats,  as  their 
faces  and  seats  become  warm.  Any  one  of  them  can  be  adjusted 
independent  of  the  other,  and  can  be  removed  from  the  valve- 
chests  by  unscrewing  four  bolts,  and  withdrawing  a  key  at  the 
point  at  which  it  is  attached  to  the  lever.  The  valve-gear  of 
these  engines  may  be  worked  by  hand,  even  under  extreme  steam 
pressure. 

The  valve-stems  of  these  engines  are  packed  with  an  improved 
metallic  packing,  Avhich  is  claimed  to  possess  many  advantages  in 
9  G 


98 


THE   engineer's  HANDY-BOOK. 


respect  to  freedom  from  friction  and  wear,  over  hemp,  cotton,  or 
any  other  fibrous  substance,  for  the  stems  of  oscillating  or  vibrat- 
ing engines,  as  illustrated  by  the  following  cut: 


Fig.  1. 


A  represents  the  valve,  B  the  valve-seat,  and  D  the  valve-stem 
or  rod,  which  is  outside  the  chest,  and  upon  the  end  of  which  is 
the  toe  with  which  the  valve-gear  engages  to  rock  the  valve  to 
enable  the  port  to  be  opened.  is  a  standard  or  bracket  pro- 
jecting from  the  side  of  the  steam-chest,  and  bolted  thereto, 
through  which  the  valve-rod  passes,  and  by  which  the  valve-rod, 
and  the  valve  connected  with  it,  are  sustained  and  supported  in 
their  proper  relation,  all  of  which  is  familiar  to  the  construction 
of  steam-engines.  At  the  inner  end  of  the  bracket,  and  con- 
centric with  the  hole  through  which  the  valve-rod  passes,  a  recess 
is  cut.  A  collar,  F,  is  then  shrunk  upon  the  valve-rod,  or  other- 
wise tightly  fitted  thereto,  so  as  to  make  a  flange,  and  is  turned 
off*  to  face  and  fit  the  recess  when  the  valve-rod, valve,  and  b?acket 
are  in  their  proper  relation.  The  face  of  the  flange,  and  the 
seat  of  the  recess,  a,  should  also  be  round,  so  as  to  make  a  steam- 
tight  joint. 

It  will  be  observed  from  above  description  that  the  Harris- 
Corliss,  while  retaining  all  the  distinctive  features  and  merits  of 
the  original  Corliss  engine,  has  in  addition  the  patented  improve- 
ments of  Self-Packing  Valve-Stems,  Stop  Motion  on  Kegulator, 
Recessed  Valve-Seats,  Drip  Collecting  Devices,  and  Piston  Packing, 


THE   engineer's  HANDY-BOOK. 


99 


Questions 

FOR  ENGINEERS,  THE  ANSWERS  TO  WHICH  WILL  BE  FOUND  UNDER 
THE  HEADS  OF  THE  RESPECTIVE  SUBJECTS  TO  WHICH  THEY  RE- 
LATE. A  PROMPT  ANSWER  WILL  SHOW  THAT  THE  CANDIDATE 
HAS  STUDIED  THE  SUBJECT,  AND  IS  MASTER  OF  THE  SITUATION, 
AND  VICE  VERSA. 

What  are  the  best  aids  to  candidates  applying  for  an  engineer's 
certificate  or  license? 

What  qualifications,  both  mental  and  physical,  ought  candi- 
dates applying  for  a  Cadetship  in  the  United  States  Navy  to  pos- 
sess? 

What  qualifications  should  candidates  for  the  position  of  en- 
gineers and  assistant  engineers  in  the  United  States  Revenue  ser- 
vice possess? 

What  ape  the  necessary  qualifications  of  applicants  for  the 
positions  of  engineers  and  assistant  engineers  in  the  Mercantile 
Marine  service? 

What  qualifications  are  necessary  for  persons  taking  charge 
of  stationary  engines  in  any  locality  requiring  a  license  ? 

Give  the  names  of  the  diflferent  triangles. 
What  is  steam? 

What  law  does  the  expansive  property  of  steam  follow? 
What  is  surcharged  steam?  • 
Will  it  aflfect  the  vacuum? 
What  is  saturated  steam? 
What  is  supersaturated  steam? 


100  THE   engineer's  HANPY-BOOK. 

To  what  are  the  temperature  and  the  elastic  force  of  steam 
equal? 

What  is  the  difference  in  the  pressure  of  steam  when  the  mer- 
cury is  in  a  vacuum,  or  when  exposed  to  the  atmosphere? 

If  the  proper  relation  of  the  temperature  between  the  steam 
and  the  water  from  which  it  is  formed  be  disturbed,  what  will  be 
the  effect? 

What  is  the  total  heat  of  steam  at  212°  Fah.? 

How  is  the  latent  heat  of  steam  found? 

When  does  heat  in  steam  become  latent? 

How  would  you  ascertain  what  amount  of  water  is  necessary  to 
condense  a  given  quantity  of  steam  ? 

What  is  low-pressure  steam? 

Why  is  the  steam  of  salt  water  fresh? 

What  is  the  most  extraordinary  property  of  steam? 

What  are  the  two  modes  of  applying  the  power  of  steam  to  the 
cylinders  of  steam-engines  ? 

State  the  rule  for  finding  the  mean  or  average  pressure  in  a 
cylinder. 

Is  the  effluent  velocity  with  which  steam  of  different  pressures 
flows  into  the  atmosphere  uniform? 

State  the  difference  between  the  latent  and  sensible  heat  of 
steam  at  different  pressures. 

State  the  total  heat  and  relative  volume  of  steam  at  different 
pressures. 


THE   engineer's   HANDY-BOOK.  101 

As  the  sensible  heat  in  steam  increases,  does  the  latent  heat 

decrease? 

In  what  way  does  the  change  affect  the  economy  of  the  steam- 
engine? 

What  is  meant  by  the  volume  of  steam? 

What  is  the  difference  in  volume  between  water,  and  steam  at 
atmospheric  pressure? 

How  much  does  one  cubic  foot  of  steam  at  atmospheric  press- 
ure weigh  ? 

State  the  velocity  with  which  steam  at  different  pressures  flows 
into  the  atmosphere  or  into  steam  of  a  lower  pressure. 

If  steam,  at  a  given  pressure,  be  cut  off  in  the  cylinder  at  a 
certain  point  of  the  stroke,  what  will  be  the  pressure  for  the  whole 
length  of  the  stroke? 

Give  the  pule  for  finding  the  amount  of  benefit  to  be  derived 
from  working  steam  expansively. 

Give  the  rule  for  finding  the  average  pressure  of  the  steam  in 
the  cylinder  for  different  points  of  cut-off. 

Is  surcharged  steam  indicated  by  the  steam-gauge?  Or  will  it 
affect  the  vacuum  ? 

What  is  superheated  steam  ? 

What  is  the  steam-jacket? 

What  is  the  difference  in  effect  between  superheated  and  sat- 
urated steam  ? 

Which  is  capable  of  producing  the  most  economical  results? 

9^ 


102 


THE   ENGINEER'S  HANDY-BOOK. 


PART  SECOND. 


Steam-Engines  in  Greneral. 

Steam-engines  embrace  a  great  variety  of  designs  and  names; 
such  as  the  beam,  side-lever,  inclined,  oscillating,  trunk,  horizontal, 
vertical,  and  steeple,  which  are  in  turn  termed  single-acting,  double- 
acting,  reciprocating,  rotary,  semi-rotary,  compound  duplex,  in- 
verted, and  geared,  each  of  which  was  probably  designed  to  meet 
some  peculiar  requirement  —  either  economy  of  space,  fuel,  or  ef- 
ficiency in  speed.  (Judging  from  the  appearance  of  things  at 
present,  the  horizontal  and  vertical  are  destined  to  supersede  all 
other  designs  for  land  and  marine  purposes.) 

All  steam-engines,  of  whatever  design,  or  for  whatever  pur- 
pose employed,  are  embraced  under  two  heads,  commonly  called 
high-  and  low-pressure,  but  more  properly  termed  condensing  and 
non-condensing.  In  the  non-condensing  engine,  the  steam,  after 
acting  on  the  piston,  escapes  into  the  open  air;  therefore  the 
pressure  of  the  outgoing  steam  must  exceed  atmospheric  pressure, 
or  14*7  lbs.  to  the  square  inch.  Thus,  if  steam  at  45  lbs.  average 
pressure  above  vacuum  be  admitted  to  the  piston  of  a  high-press- 
ure engine,  it  will  exert  a  force  equal  to  its  pressure ;  but  14*7 
lbs.  per  square  inch  of  that  pressure  will  not  be  converted  into 
work,  as  it  will  be  lost  in  overcoming  the  pressure  of  the  atmos- 
phere, which  may  be  illustrated  by  the  following  example : 

Diameter  of  cylinder,  12  in. ;  area,  113*09  in. 

Average  steam  pressure  per  square  inch,  45  lbs. 

Total  steam  pressure,  5089*05  lbs. 

As  before,  area,  113*09  sq.  in. 

Atmospheric  pressure,  14*7  lbs. 

Total  atmospheric  pressure,  1662*423  lbs.  . 

5089*050 

Loss  due  to  atmospheric  pressure,  1662*423 
Effective  steam  pressure  on  piston,  3426  627  lbs. 


THE   ENGINEER'S  HANDY-BOOK. 


103 


The  foregoing  example  shows  the  resistance  to  be  overcome  at 
each  stroke  of  the  piston  before  the  steam  acting  against  it  can 
produce  any  useful  effect.  Thus  it  will  be  seen  that  the  piston 
of  a  high-pressure  steam-engine  is  exposed  to  the  action  of  two 
pressures,  namely,  the  pressure  of  the  sLeam  from  the  boiler  on 
one  side,  and  that  due  to  the  atmosphere  and  the  steam  remaining 
in  the  cylinder  after  exhaust  takes  place  on  the  other.  The 
pressure  utilized  or  converted  into  work  will  be  the  difference 
between  the  two. 

In  the  low-pressure  or  condensing  engine,  the  steam,  after 
acting  against  the  piston,  escapes  into  a  condenser,  where  it  is 
condensed  into  water  and  a  vacuum  is  formed  ;  thus  rendering  not 
only  a  considerable  portion  of  the  steam  pressure  in  the  boiler, 
but  also  the  14*7  lbs.  per  square  inch  required  in  the  non-con- 
densing engine  to  overcome  the  pressure  of  the  air,  available  as  an 
effective  force  against  the  piston,  which  maybe  explained  as  follows: 

Diameter  of  cylinder,  12  in. ;  area,  113*09  sq.  in. 
Average  steam  pressure  per  square  inch,  45  lbs. 

Total  effective  steam  pressure,  o089'05  lbs. 
As  before,  area,  113*09  sq.  in. 
Vacuum  at  best,  13  lbs. 

Power  due  to  vacuum,  1470*17  lbs. 

3958*15 
1470-17 

Total  effective  pressure  due  to  steam  and  vacuum,  5428*32  lbs. 

The  back  pressure  in  the  condenser,  which  represents  the  differ- 
ence between  the  indications  of  the  vacuum-gauge  and  a  perfect 
vacuum, must  be  deducted;  but,  as  a  perfect  vacuum  is  not  attain- 
able, the  back  pressure  varies  from  2  to  5  lbs.,  according  to  the 
condition  of  the  engine  and  the  quantity  of  uncondensed  steam 
remaining  in  the  condenser. 

Waste  in  the  high-pressure  engine.  — In  the  best  types  of 
modern  high-pressure  engines,  the  useful  effect  obtained  from  the 
work  stored  up  in  good  fuel  may  be  calculated  as  follows : 


104 


THE   ENGINEER'S  IIANDY-BOOK. 


Loss  through  bad  firing  and  incomplete  combustion,  10  per  cent. 
Carried  off  by  draught  through  chimney,  30   "  " 

Carried  away  in  the  exhaust  steam,  50   "  " 

Utilized  in  motive  power  (indicated),  10  "  " 

100  per  cent. 

The  foregoing  may  seem  incredible,  and  yet  any  one  wishing 
to  do  so  may  demonstrate  its  truthfulness  to  his  own  satisfaction 
by  placing  a  thermometer  in  the  steam-pipe  and  noting  its  tem- 
perature during  its  escape  from  the  boiler  to  the  cylinder ;  then 
placing  it  in  the  exhaust-pipe,  close  to  the  engine,  and  noting  the 
temperature  at  this  point,  when  it  will  be  discovered  that  the 
steam  has  lost  very  little  of  its  heat  in  passing  through  the  cyl- 
inder. Consequently  the  difference  in  temperature  between  the 
steam  when  it  escapes  from  the  boiler  and  from  the  exhaust-pipe, 
constitutes  all  of  the  heat  that  was  contained  in  the  fuel  that  was 
utilized. 

Waste  in  the  low-pressure  or  condensing  engine. — According 
to  the  dynamic  theory  of  heat,  as  shown  on  page  105,  a  certain 
weight  of  coal  contains  within  itself  a  certain  amount  of  work 
stored  up,  and  ready  to  rush  out  under  the  necessary  surround- 
ings, as  in  the  case  of  a  compressed  spring  set  free.  The  supply 
of  a  given  weight  of  coal  to  the  furnace  of  a  steam-boiler  repre- 
sents the  application  of  a  definite  amount  of  force  at  one  end  of 
a  series  of  transformations,  a  part  of  which  force  at  length 
appears  as  useful  work  at  the  other,  the  balance  having  been 
wasted  in  the  various  processes  through  which  it  has  passed. 

Take,  for  example,  a  modern  marine-engine  of  the  best  con- 
struction and  design.  The  force  supplied  to  the  furnace  in  the 
combustible  is  first  developed  as  heat  by  the  burning  of  the  coal ; 
a  portion  of  this  heat  is  utilized  in  changing  the  water  into 
steam,  the  balance  being  wasted  either  in  radiation,  or  by  being 
carried  off  in  the  hot  gases  through  the  chimney.  A  part  of  the 
steam  formed  is  applied  to  move  the  piston,  the  remainder  being 
wasted  by  condensation  against  the  sides  of  the  pipes  and  cylin- 


THE   ENGINEER'S  HANDY-BOOK. 


105 


ders,  and  by  leakage  past  the  piston  or  valves  into  the  con- 
denser. 

It  is  thus  shown  that  only  a  small  portion  of  the  total  force 

contained  in  the  steam  that  is  applied  to  move  the  piston  is  util- 
ized. Of  the  force  that  is  utilized  in  the  cylinder,  only  a  small 
portion  performs  any  external  work,  the  remainder  being  absorbed 
in  overcoming  the  back  pressure  induced  by  the  friction  of  the 
machine  itself.  Of  the  remaining  small  portion  that  may  be  ap- 
plied to  the  screw,  another  part  is  wasted  in  overcoming  its  use- 
less resistances,  and  only  the  balance  used  to  propel  the  ship. 


PER  CENT. 

1  Uldl  iludl  III  Uilv  ilUflUI  CU  lUo.  (Ji  d,llllll<x~ 

pifp  pojil   in  units  of  heat,...  

1  400  000 

Deduct  heat  equivalent  to  weight  of 

200,000 

J.Oiai    lltJd;L   111    Ullc    11U11U.1  tJtl  lUb.  Ul  d;ll- 

1,200,000 

100 

Carried  off  by  hot  gases  in  chimney... 

200,000 

163 

1,000,000 

83| 

Lost  by  leakage  and  condensation  

200,000 

161 

Available  to  perform  work  in  cylinder. 

800,000 

661 

Escaped  with  steam  into  condenser  

660,000 

55 

140,000 

llf 

Absorbed  in  overcoming  resistance  of 

40,000 

H 

100,000 

Absorbed  in  useless  resistance  of  the 

20,000 

Is 

Usefully  applied  to  propel  the  ship  

80,000 

The  following  figures  represent  approximately  the  supposed 


106 


THE   ENGINEER'S  HANDY-BOOK. 


distribution  of  the  total  force  in  the  best  engines.  No  estimate  is 
taken  in  them  of  the  coal  that  is  consumed  in  various  ways  on 
board  ship  other  than  those  mentioned,  as,  for  instance,  in  getting 
up  steam,  or  in  steam  used  to  work  pumps,  in  steam  lost  through 
the  safety-valves,  in  heat  lost  in  blowing  off,  or  remaining  in  the 
furnaces  after  the  vessel  has  arrived  in  port.  These  and  other 
causes  usually  add  at  least  ten  per  cent,  to  the  consumption, 
leaving  the  force  utilized  about  six  per  cent,  of  the  total  force  ex- 
pended in  the  coal.  The  cost  of  an  indicated  horse-power,  by  the 
figures,  would  be  2i  lbs.  of  coal  per  hour  nearly. 

To  mitigate  as  far  as  possible  the  foregoing  losses,  the  surface- 
condenser  and  boiler  arrangements  shduld  be  designed  so  as  to 
insure  a  rapid  circulation  of  the  water,  that  condition  being  of  the 
greatest  importance  to  produce  efficiency  in  the  heating  or  cooling 
surfaces.  Whenever  practicable,  the  feed-water  should  be  used 
as  injection  to  condense  the  educted  steam,  so  that  it  might  be 
heated  to  the  highest  possible  point  before  Being  sent  into  th^ 
boiler. 

It  is  a  question  of  vital  importance  to  the  owner  of  a  steamship, 
that  the  consumption  of  fuel  be  reduced  to  the  lowest  possible 
amount,  as  each  ton  of  fuel  excludes  a  ton  of  cargo.  As  improve- 
ments in  the  form  of  the  hull  and  machinery  are  eflfected,  less 
power  and  less  fuel  will  be  required  to  propel  a  vessel  through  the 
water  a  given  distance ;  but,  great  as  have  been  the  improvements 
effected  in  marine  engines  to  this  end,  much  yet  remains  to  be 
accomplished,  as  while  the  consumption  of  fuel  has  been  reduced, 
by  working  steam  more  expansively  in  vessels  of  later  date,  from 
three  or  four  to  less  than  two  pounds  per  effective  horse-power, 
yet,  comparing  this  with  the  total  amount  of  energy  in  two  pounds 
of  coal,  it  will  be  found  that  not  a  tenth  part  of  the  power  is  ob- 
tained which  that  amount  of  coal  would  theoretically  call  into 
action. 

To  find  the  quantity  of  coal  required  to  drive  a  steamship  a 
given  number  of  days  in  average  fair  weather.  The  beam  in  feet 
squared  will  give  the  quantity  of  coal  required  in  net  tons.  But 


THE   engineer's   HANDY-BOOK.  107 


it  must  be  understood  that,  with  equal  beams,  the  displacement, 
and  consequently  the  power  required,  vary  very  much ;  or,  in 
other  words,  the  displacement  is  not  always  proportionate  to  the 
beam  in  vessels  of  the  same  model,  nor  is  the  power  required  to 
propel  them  always  proportionate  to  the  displacement. 

When  steamships  are  running  through  still  water  and  still  air, 
the  loss  due  to  the  resistance  of  the  atmosphere  is  about  ten  per 
cent,  of  the  whole  power  expended,  ninety  per  cent,  being  absorbed 
in  overcoming  the  resistance  of  the  water. 

Economy  of  the  condensing  over  the  non-condensing  engine. — 
When  the  resistance  of  the  atmosphere  is  removed  from  the  piston, 
the  sleam  ifl'ay  be  cut  off*  earlier,  and  further  expanded  in  the 
cylinder.  This  reduces  the  draught  on  the  boiler,  and  admits  of  a 
slower  combustion  of  the  fuel.  In  this  way  economy  is  promoted 
by  condensation  of  the  exhaust  steam  and  by  the  vacuum  formed 
in  the  cylinder.  A  vacuum  equal  to  14  lbs.  per  square  inch  is 
35  per  cent,  saving  in  fuel,  or  the  same  increase  in  power ;  but 
this  saving  undergoes  a  great  reduction,  in  consequence  of  the 
cylinder  being  open  alternately  to  the  lower  temperature  in  the 
condenser,  which  varies  with  the  degree  of  expansion  employed, 
being  least  when  the  steam  follows  full  stroke,  which  is  very 
seldom  the  case.  The  practical  gain,  therefore,  in  the  condensing 
engine  is  from  20  to  30  per  cent.,  varying  with  the  conditions 
above  named,  as  shown  in  the  working  of  condensing  engines, 
both  stationary  and  marine.  The  economy  of  the  condensing  en- 
gine might  be  increased,  if  advantage  could  be  taken  (as  in  the 
case  of  the  injector  and  steam-jet)  of  the  velocity  with  which  the 
exhaust  steam  escapes  from  the  cylinder  to  the  condenser.  On 
entering  the  condenser,  the  power  due  to  its  energy  is  entirely  de- 
stroyed by  the  cold  water  injection,  or  by  being  brought  in  contact 
with  refrigerating  surfaces. 

Economy  in  modern  steam-engines,  condensing  and  non-con- 
densing.— In  Watt's  time,  1  cubic  foot  or  62 •>  lbs.  of  water  was 
the  allowance  per  horse-power  per  hour  for  average  engines,  but 
the  water  consumption  for  most  engines  was  from  75  to  80  lbs. ; 


108  THE   ENGINEER'S  HANBY-BOOK. 

while  the  better  class  of  modern  automatic  cut-off  high-pressure 
engines  will  yield  a  horse-power  from  a  water  consumption  of 
from  20  to  25  lbs.,  and  in  the  best  class  of  condensing  engines  of 
from  18  to  22  lbs. ;  but,  in  either  case,  the  water  consumption  de- 
pends a  good  deal  on  the  size  of  the  engines,  and  the  excellence 
of  the  design  and  workmanship,  quality  of  steam,  pressure,  etc. 
The  last  condition  exerts  a  very  important  influence  on  the  quan- 
tity of  water  required  to  develop  a  horse-power. 

The  mean  effective  pressure  on  the  piston  of  a  steam-engine 
is  the  exponent  of  the  work  performed.  The  term  "  effective 
pressure  "  means  the  amount  by  which  the  total  pressure  behind 
the  piston  exceeds  that  which  acts  on  the  other  side  in  opposition 
to  its  movement.  The  terminal  pressure,"  or  that  at  which  the 
steam  releases  itself  from  the  cylinder,  is  the  corresponding  expo- 
nent of  the  consumption  of  water  by  the  engine,  or  the  cost  of  the 
power.  Hence,  the  best  economy  is  attained  when  the  mean  effec- 
tive pressure  is  highest  relatively  to  the  terminal  pressure ;  and 
anything  that  will  increase  the  former  without  correspondingly 
increasing  the  latter,  or  which  will  diminish  the  latter  without  cor- 
respondingly diminishing  the  former,  will  improve  the  economy. 

The  difference  in  effect  between  the  condensing  and  non-con- 
densing engine,  with  equal  pressure  of  steam  and  expansion,  is 
solely  that  the  condensing  engine  has  the  advantage  of  the  effect 
produced  by  the  vacuum,  or  the  amount  of  atmospheric  pressure 
removed.  Their  difference  in  operation  is,  that  in  the  condensing 
engine,  the  steam,  after  having  performed  its  duty  in  the  cylinder, 
is  condensed  by  the  admission  of  a  spray  of  cold  water,  or  being 
brought  in  contact  with  cooling  surfaces,  thus  producing  a  vacuum 
or  minus  pressure,  which  varies,  according  to  the  perfection  of  the 
machinery,  from  10  to  13  lbs.  per  square  in.;  while  in  the  non-con- 
densing engine,  the  steam,  after  having  performed  its  duty,  is 
discharged  into  the  atmosphere.  Thus,  the  advantages  of  the 
vacuum  are  lost ;  some  of  the  waste  heat,  however,  is  utilized  by 
leading  the  exhaust  steam  through  a  heater,  for  the  purpose  of 
heating  the  feed-water. 


THE   ENGINEEr\s  HANDY-BOOK. 


109 


Compound  Engines. 

A  compound  engine  is  a  high-  and  low-pressure  condeDsing 
engine,  with  two  cylinders  and  pistons.  The  steam  is  first  ad- 
mitted to  the  small  or  high-pressure  cylinder,  until  the  piston  has 
moved  through  a  certain  distance,  when  the  valve  is  so  regulated, 
that  the  communication  with  the  boiler  is  cut  off,  the  remainder 
of  the  space  to  be  passed  through  by  the  piston  being  performed 
by  the  expansion  of  the  steam,  which,  having  done  its  work,  es- 
capes to  the  condensing  cylinder,  where  it  does  a  proportionate 
amount  of  work,  and  out  of  which  it  escapes  into  the  condenser. 

With  respect  to  the  number  and  arrangements  of  the  cranks 
and  cylinders  of  compound  engines,  there  are  five  or  six  designs 
used  for  screw  propulsion  ;  but  the  most  generally  adopted  is  the 
inverted,  vertical,  direct-acting,  with  the  cylinders  both  high-  and 
low-pressure,  placed  alongside  of  each  other  in  the  fore  and  aft 
direction  of  the  ship,  and  the  steam-chests  between  them  con- 
nected direct  with  the  two  cranks  on  the  shaft  beneath.  Another 
kind  is  that  of  an  inverted,  direct-acting  engine,  with  one  cylinder 
placed  above  the  other,  the  high-pressure  being  uppermost.  In 
this  case  there  is  only  one  piston-rod,  which  is  continued  through 
both  cylinders  and  pistons,  one  connecting  and  consequently  only 
one  crank,  a  fly-wheel  being  generally  employed  to  assist  the 
engine  in  passing  over  the  centres.  In  another  type,  which  is 
known  as  the  Huntoon,  the  high-pressure  cylinder  is  placed 
within  the  low-pressure.  In  another,  known  as  the  Smart  en- 
gine, there  are  four  cylinders  —  two  high-pressure  and  two  low  ; 
the  two  high-pressure  cylinders  being  placed  on  the  tops  of  the 
low  ones,  the  piston-rods  passing  through  both  cylinders  and  con- 
nected directly  with  the  cranks.  Lastly,  the  design  most  gener- 
ally adopted  for  war-vessels  is  the  horizontal,  in  which  the  cylin- 
ders are  placed  side  by  side. 

It  is  claimed  that  in  the  better  class  of  compound  engines  2 
lbs.  of  coal  will  develop  a  horse-power ;  but  the  want  of  reliable 
data  to  the  contrary  would  warrant  the  assertion  that  3  lbs.  of 
10 


110  THE   ENGINEER'S  HANDY-BOOK. 


THE   ENGINEER'S  HANDY-BOOK, 


111 


F 


The  annexed  cut  represents  the  section  through  the  cylinders,  steam-chests, 
cross-heads,  pillow-blocks,  etc.,  of  a  Compound  Marine  Engine.  ^4, 
sViow  the  high-  and  low-pressure  cylinders  ;  B,  B,  the  pistons ;  G,  G,  the 
piston-rods;  D,  Z),  the  steam-chests;  E,  E,  the  exhaust  cavities;  E^  E^ 
v:ilve-rod  guides;  H,  connecting-rods;  7,  J,  cranks;  J,  J,  crank-shaft  ; 
K,  Ky  Kj  pillow-blocks ;  X,  2v,  foundation-plate ;  c,  c,  cross-heads ;  a,  a, 
h,  6,  cross-head-guides;  d,  d,  eccentrics.  The  steam  is  admitted  from 
the  boilers  to  the  steam-chest  of  the  high-pressure  cylinder,  from  which 
it  is  exhausted  into  the  receiver  and  readmitted  into  the  low-pressure 
cylinder,  after  which  it  escapes  to  the  condenser. 


112  THE   engineer's  HANDY-BOOK. 

coal  are  oftener  consumed  in  the  development  of  a  horse-power 
than  2  lbs.  Taking  3  lbs.  as  equivalent  to  a  horse-power  per 
hour,  theoretically  only  about  one-sixteenth  part  has  been  util- 
ized. The  advantages  of  compound  over  simple  engines  is  an 
open  and  unsettled  question,  as  it  is  claimed  that  some  "simple 
engines  in  use  at  the  present  time  are  more  economical  in  the  use 
of  fuel  than  compound  engines ;  but  economy  of  fuel  is  not  the 
only  consideration  which  leads  to  a  choice  of  the  compound  en- 
gine for  marine  service,  since,  perhaps,  the  more  equal  distribu- 
tion of  the  power  throughout  the  stroke  is  a  feature  of  value  in 
these  as  in  all  other  engines  where  the  resistance  is  devoid  of  the 
controlling  influence  of  the  fly-wheel.  The  disadvantages  of  com- 
pound engines  are  their  extreme  first  cost,  extra  weight,  and  com- 
plication of  parts. 

The  receiver  is  a  chamber  between  the  cylinders  of  compound 
engines  into  which  the  steam  from  the  high-pressure  cylinder  es- 
capes, and  from  which  it  is  admitted  to  the  low-pressure  cylinder. 
The  receiver  may  be  said  to  be  the  steam-drum  for  a  low-pressure 
cylinder ;  its  capacity  might  be  infinite,  except  for  the  weight  and 
expense  it  would  incur.  In  the  majority  of  independent  com- 
pound engines,  the  capacity  of  the  receiver  is  about  equal  to  that 
of  the  low-pressure  cylinder,  though  for  engines  in  general  its 
capacity  is  regulated  by  certain  attending  circumstances.  Such 
engines  as  the  Worthington  have  no  receivers. 

Simple  Engines. 

All  steam-engines  are  divisible  into  two  classes,  simple  and 
compound  ;  the  latter  being  those  in  which  the  steam  is  used 
twice,  by  being  exhausted  from  one  cylinder  into  another,  while 
the  former  applies  to  all  engines  which  use  steam  only  once, 
whether  they  are  double  engines  and  have  double  sets  of  valve- 
gear  or  not.  The  term  single  engine  is  sometimes  used ;  but  it 
is  liable  to  give  rise  to  confusion. 

Locomotives,  steam  fire-engines,  and  stationary  engines  which 


THE   engineer's  HANDY-J500K. 


113 


take  their  steam  directly  from  the  boiler  and  exhaust  it  into  the 
atmosphere  should  be  termed  simple  engines,  regardless  of  the 
number  of  cylinders.  An  impression  very  generally  prevails 
among  engineers  that  compound  engines  are  of  necessity  marine 
engines,  and  also  condensing,  which  is  a  mistake,  as  there  are 
both  high-pressure  and  low-pressure,  or  condensing  and  non- 
condensing  compound  engines.  Condensing  compound  engines 
generally  have  not  more  than  two  cylinders,  although  in  some 
instances  they  have  three,  while  non-condensing  compound  en- 
gines are  met  with  which  have  four. 

Marine  Engine.  —  The  term  marine  engine  is  in  very  common 
use,  but  it  has  no  definite  meaning,  as  it  may  be  either  condensing 
or  non-condensing,  vertical,  horizontal,  or  inclined,  simple  or 
compound.  The  only  reason  that  can  be  assigned  for  designating 
it  a  marine  engine  is  that  it  was  designed  to  be  used  on  steam- 
ships. A  marine  engine,  properly  speaking,  is  an  engine  designed 
to  occupy  a  certain  space  on  a  vessel,  and  be  capable  of  developing 
a  certain  amount  of  power.  The  most  desirable  class  of  marine 
engines  are  those  that  develop  the  greatest  amount  of  power  with 
a  given  area  of  piston  and  steam  pressure,  and  that  occupy  the 
least  space.  The  vertical  engine  is  more  in  favor  with  marine 
engineers,  as  it  possesses  many  advantages  over  any  other  design. 
This  perhaps  arises  from  the  fact  that  it  occupies  less  floor  space ; 
that  it  is  more  compact,  and  less  liable  to  spring  than  an  engine 
of  any  other  design ;  and  that  the  weight  is  against  the  lifting- 
force  of  the  reciprocating  and  revolving  mechanism  ;  also  that,  in 
consequence  of  the  housing  and  pillow-block  bearings  being  in  one 
piece,  they  are  less  liable  to  get  out  of  line  than  those  of  any  other 
arrangement;  and  that  they  afford  better  facilities  for  a  direct 
connection  with  the  propeller  shaft  than  any  other.  Trunk  and 
oscillating  engines  are  still  employed  in  England  for  marine  pur- 
poses, but  only  on  war-vessels.  Such  designs  never  were  looked 
upon  with  much  favor  by  enlightened  engineers. 
10*  H 


114 


THE   engineer's  HANDY-BOOK. 


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116 


THE   ENGINEER'S  HANDY-BOOK. 


Uncertainty  of  Tests  made  for  the  Purpose  of  Comparing 
the  Relative  Economy  of  Marine  Engines. 

It  has  been  customary  heretofore,  in  order  to  determine  the 
relative  economy  of  marine  engines,  to  weigh  the  amount  of  coal 
consumed  in  performing  a  certain  amount  of  work.  So  long  as 
all  the  machines  compared  are  of  the  same  design  and  dimensions, 
the  coal  used  of  the  same  kind  and  quality,  and  the  pressure  of 
the  steam,  the  degree  of  vacuum,  the  rate  of  expansion,  the  tem- 
perature of  the  atmosphere,  and  all  other  circumstances  are  the 
same,  it  may  be  inferred  that  any  difference  in  the  economy  is  the 
result  of  some  imperfection  in  the  engine  itself.  But  if  there  is  a 
variation  in  one  particular  only,  as,  for  instance,  in  the  degree  of 
vacuum,  the  difference  may  be  assumed  to  be  due  to  that  varia- 
tion ;  but  if  there  are  several  variations  at  the  same  time,  where 
there  are  different  kinds  of  engines  or  boilers  and  different  steam- 
pressures,  when  there  is  any  gain  or  loss  of  economy,  it  is  impos- 
sible to  decide  to  which  of  the  variations  the  change  is  due.  So, 
also,  where  high  pressure  of  steam  is  carried,  and  a  greater  expan- 
sion is  employed,  if  a  poor  economy  is  shown,  it  may  happen  that 
the  benefits  that  should  result  from  the  high  pressure  and  the  in- 
creased expansion  were  counteracted  by  the  increased  condensa- 
tion and  leakage,  or  that  the  power  which  was  gained  in  the 
engine  was  lost  in  the  boiler,  or  vice  versa.  Then,  again,  any  dif- 
ference in  the  kind  of  fuel  employed,  or  in  the  skill  and  manage- 
ment, unite  with  the  other  variations  to  render  the  actual  results 
more  unsatisfactory. 

In  attempting  to  compare  the  results  of  such  experiments  as 
^  are  recorded  to  determine  the  most  economical  design  of  engine, 
it  will  be  generally  found  that  the  experiments  made  to  determine 
one  certain  point  are  not  sufficiently  complete  to  serve  any  other 
purpose,  and  have  generally  been  made  by  different  men,  under 
different  circumstances  and  in  different  localities ;  and,  moreover, 
that  the  expert  is  almost  invariably  biassed  by  prejudice.  This 
is  particularly  applicable  to  the  reports  which  may  be  obtained 


THE   engineer's  HANDY-BOOK. 


117 


of  the  performances  of  new  and  improved  engines,  which  may  be 
accounted  for  in  this  way :  A  steamship  company  may  place  on 
its  lines  a  vessel  of  fine  model,  with  the  most  improved  machinery, 
which,  on  comparison,  would  show  more  satisfactory  results  than 
one  of  the  same  capacity  but  of  inferior  lines,  and  propelled  by 
an  inferior  style  of  engine.  It  will  be  found,  on  comparison,  that 
the  profits  resulting  from  the  new  ship  and  improved  engines  are 
largely  in  excess  of  those  of  the  old;  but  it  would,  at  the  same 
time,  be  diflScult  to  separate  the  gain  due  to  the  improvement  in 
the  model  of  the  hull  from  that  due  to  the  improved  engines,  and 
vice  versd.  All  that  can  be  done  in  such  cases  is  to  accept  the 
whole  result,  without  being  able  to  separate  the  one  from  the 
other.  'A  series  of  exhaustive  experiments  to  determine  the 
relative  economy  of  different  classes  of  steam-engines  and  boilers 
is  very  much  needed,  but  the  diflficulties  to  be  encountered  are  so 
numerous  as  to  render  such  an  undertaking  impracticable. 

Power  of  steam-engines. — The  power  which  a  steam-engine 
can  furnish  is  generally  expressed  in  "  horse-power,''  the  "  nominal 
horse-power "  being  admitted  to  be  a  force  capable  of  raising  a 
weight  of  33,000  pounds  *  one  foot  high  in  one  minute,  or  150 
pounds  220  feet  high  in  the  same  length  of  time.  If  an  engine  is 
rated  at  25  horse-power,  it  is  recognized  as  being  capable  of  rais- 
ing 33,000  pounds  one  foot  high  twenty-five  times  in  each  minute. 
The  question  will  naturally  arise.  How  are  these  33,000  pounds  to 
be  raised  ?  The  answer  to  which  would  be,  by  belts,  pulleys,  cog- 
gearing,  cables,  paddle-wheels ,  screw-propellers,  or  whatever  mechan- 
ical arrangement  is  most  practicable  and  convenient. 

There  are  several  terms  employed  to  express  the  power  of  en- 
gines, such  as  the  "  nominal,"  "  indicated,"  "  actual  or  net,"  "  dy- 
namo-metrical," and  "  commercial "  horse-power.  The  indicated 
horse-power  is  obtained  by  multiplying  together  the  mean  efifective 
pressure  in  the  cylinder  as  shown  by  the  diagram,  the  area  of  the 
piston  in  square  inches,  and  the  speed  in  feet  per  minute,  and 


Foot-pounds. 


118  THE   ENGINEER'S  HANDY-BOOK. 

dividing  the  product  by  33,000.  The  actual  or  net  horse-power 
is  the  total  available  power  of  an  engine ;  it  equals  the  indicated 
horse-power  less  the  amount  expended  in  overcoming  the  friction. 
The  dynamo-metrical  horse-power  is  the  net  horse-power  after 
allowing  for  friction.  The  term  commercial  horse-power  is  some- 
times used,  but  has  no  definite  meaning,  as  there  is  no  recognized 
rule  among  engineers  by  which  to  buy  or  sell  engines. 

Estimating  the  power  of  steam-engines. — There  are  three  con- 
ditions necessary  to  be  understood,  before  we  can  calculate  with 
any  degree  of  accuracy  the  power  which  a  steam-engine  is  capa- 
ble of  developing — first,  the  number  of  square  inches  in  the 
piston ;  second,  the  effective  pressure  exerted  against  each  square 
inch  of  the  same ;  third,  the  speed  of  the  piston  in  feet  per  minute. 
Nor  can  the  power  which  a  steam-engine  is  exerting  be  demon- 
strated by  any  calculation,  however  accurate,  unless  the  condition 
of  the  engine  and  the  back  pressure  be  also  known,  which  latter 
can  only  be  determined  by  the  indicator. 

How  to  increase  the  power  of  steam-engines.— The  three  most 
practical  methods  of  increasing  the  power  of  a  steam-engine  are, 
1st.  To  enlarge  the  diameter  of  the  cylinder ;  2d.  To  increase  the 
speed;  3d.  To  increase  the  pressure  of  the  steam.  But  the  in- 
crease in  any  case  must  have  a  very  narrow  limit,  as,  if  the  diam- 
eter of  the  cylinder  be  increased  much,  the  other  parts  of  the  en- 
gine will  be  too  light.  The  steam  pressure  cannot  be  increased 
more  than  the  boiler  can  safely  bear,  nor  can  the  speed  be  in- 
creased beyond  what  the  revolving  and  reciprocating  parts  of  the 
engine  will  bear.  But  the  power  of  any  high-pressure  engine  can 
be  very  materially  increased  by  attaching  a  condenser  and  an  air- 
pump  to  it,  providing  the  water  supply  is  sufficient. 

Speed  of  engines. — The  speed  of  steam-engines  is  generally 
counted  by  strokes,  one  stroke  being  half  a  revolution,  or  one 
revolution  being  two  strokes.  The  crank  travels  from  one  dead- 
centre  to  the  other  to  make  one  stroke,  the  distance  travelled  by 
the  crank-pin  while  making  a  stroke  being  twice  the  distance  be- 
tween the  centres  of  the  crank-pin  and  crank-shaft.    To  find  the 


THE   engineer's    HANDY-BOOK.  119 


travel  of  piston  in  feet  per  minute,  multiply  the  distance  travelled 
for  one  stroke  in  inches  by  the  whole  number  of  strokes  in  inches, 
and  divide  by  12. 

Over-stroke. — This  term  is  used  when  the  position  of  the  piston 
in  the  cylinder  is  so  altered  by  taking  up  the  lost  motion  in  the 
boxes  that  it  strikes  either  cylinder-head  when  the  crank  is  at 
the  dead-centre. 

The  Locomotive.* 

In  estimating  the  power  of  a  locomotive,  the  term  horse-power 
is  not  generally  used,  as  the  difference  between  a  stationary  steam- 
engine  and  a  locomotive  is,  that  while  the  stationary  engine  raises 
its  load,  or  overcomes  any  directly  opposing  resistance  with  an 
effect  due  to  its  capacity  of  cylinder,  the  load  of  a  locomotive  is 
drawn,  and  its  resistance  must  be  adapted  to  the  simple  adhesion 
of  the  engine,  which  is  the  measure  of  friction  between  the  tires 
of  the  driving-wheels  and  the  surface  of  the  rails. 

The  power  of  the  locomofive  is  estimated  in  the  moving  force 
at  the  tread  of  the  tires.  It  is  called  the  tractive  force,  and  is 
equivalent  to  the  load  the  locomotive  could  raise  out  of  a  pit  by 
means  of  a  rope  passed  over  a  pulley  and  attached  to  the  circum- 
ference of  the  tire  of  one  of  the  driving-wheels.  The  adhesive 
power  of  a  locomotive  is  the  power  of  the  engine  derived  from  the 
weight  on  its  driving-wheels,  and  their  friction  or  adhesion  to  the 
rails. 

If  the  wheels  of  a  locomotive  were  geared  into  toothed  rails, 
its  power  would  be  the  force  w^ith  which  its  wheels  could  be  made 
to  turn,  or  the  weight  or  force  which,  if  applied  at  the  rims  of 
the  wheels,  would  prevent  them  from  turning.  But  if  the  wheels 
revolve  on  smooth  rails  and  slip  in  turning,  a  part  of  the  power 
would  be  wasted,  and  the  effective  power  of  the  engine  limited  by 
the  friction  or  adhesion  of  its  driving-wheels.    Hence  the  terms 

^For  full  particulars  on  this  subject,  see  Roper's  "Hand-Book  of  the 
Locomotive." 


120 


THE   engineer's  HANDY-BOOK. 


"tractive  power'' and  "adhesive  power"  mean  respectively  the 
revolving  power  and  the  progressive  power  of  the  engine. 

The  Steam  Fire-Engine.* 

Steam  fire-engines  are  simply  hydraulic  machines  similar  to 
steam-pumps,  and  the  conditions  involved  in  their  employment 
are  precisely  the  same.  They  are  also  steam-engines,  with  their 
machinery  adapted  to  a  special  purpose,  it  being  perfectly  imma- 
terial whether  they  are  movable  or  stationary.  Their  means  of 
locomotion  is  only  a  matter  of  convenience.  The  result  of  the 
working  of  the  steam  fire-engine  may  be  measured  by  the  hydraulic 
effect,  and  the  power  utilized  may  be  determined  by  the  quantity 
of  water  delivered. 

To  determine  the  efficiency  of  steam  fire-engines,  it  is  necessary 
to  note  — first,  the  extreme  vertical  height  and  horizontal  distance 
to  which  the  water  can  be  thrown  ;  second,  the  volume  or  quantity 
delivered  in  a  certain  time ;  tliird,  the  total  power  consumed  in 
performing  that  work. 

IKu\q  for  finding  the  horse-power  of  steam-engines. 

Multiply  the  area  of  the  piston  in  inches  by  the  average  steam 
pressure  in  pounds  per  square  inch ;  multiply  this  product  by  the 
travel  of  the  piston  in  feet  per  minute,t  divide  this  product  by 
33,000 ;  the  quotient  is  the  horse-power. 

for  finding  the  horse-power  of  steam  fire-engines. 

Multiply  the  area  of  the  piston  in  inches  by  the  steam  pressure 
in  pounds  per  square  inch ;  multiply  this  product  by  the  travel 
of  the  piston  in  feet  per  minute,  and  divide  this  last  product  by 
33,000 ;  '1  of  the  quotient  will  be  the  horse-power. 

1{\x\q  for  finding  the  horse-power  of  a  locomotive. 

Multiply  the  area  of  the  piston  in  inches  by  the  pressure  in 

^For  a  full  description  of  all  the  steam  fire-engines  in  use  at  the  present 
day,  their  peculiarities  of  design,  construction,  efficiency,  etc.,  see  Roper's 
"  Hand-Book  of  Modern  Steam  Fire-Engines." 

f  Which  should  never  be  less  than  250  feet  per  minute ;  in  fact,  that  should 
be  the  minimum  piston  speed  for  all  classes  of  engines. 


THE   ENGINEER'S  HANDY-BOOK. 


121 


pounds  per  square  inch;  multiply  this  product  by  the  number 
of  revolutions  per  minute;  multiply  this  by  twice  the  length  of 
the  stroke  in  feet  or  inches;  multiply  this  last  product  by  2  and 
divide  by  33,000;  the  result  will  be  the  horse-power. 

Rule  for  finding  the  horse-power  of  simple  condensing  engines. 

Multiply  the  area  of  the  piston  in  inches  by  the  mean  effective 
pressure  in  pounds  per  square  inch  ;  multiply  this  product  by  the 
velocity  of  the  piston  in  feet  per  minute  ;  multiply  the  atmos- 
pheric pressure  in  pounds  per  square  inch  on  the  bucket  of  the 
air-pump  by  its  velocity  in  feet  per  minute;  subtract  the  last 
product  from  the  second,  and  divide  the  remainder  by  33,000 ;  the 
quotient  will  be  the  horse-power  of  the  engine. 

In  estimating  the  hopse-power  of  steam-engines  by  the  fore- 
going rules,  not  more  than  two-thirds  of  the  boiler  pressure  should 
be  taken  ;  as  the  analysis  of  a  large  number  of  indicator  diagrams 
shows  that  the  average  pressure  in  the  cylinders  of  slide-valve 
engines  rarely,  if  ever,  exceeds  two-thirds  of  the  boiler  pressure. 
This  difference  is  due  to  the  reduction  caused  by  the  pipes,  stop- 
valves,  and  the  condensation  in  the  pipes,  cylinder,  etc. 

Rule  for  finding  the  horse-power  of  a  steam-engine  by  indicator 
diagrams. 

Multiply  the  area  of  the  piston  by  its  travel  in  feet  per  minute, 
and  divide  by  33,000;  the  quotient  will  be  the  value  of  one  pound 
of  mean  effective  pressure,  which,  if  multiplied  by  the  total  mean 
effective  pressure,  as  shown  by  the  card,  will  give  the  indicated 
horse-power. 

Example. — Area  of  piston,  113. 

Travel  of  piston  in  feet  per  minute,  333 1. 

113  X  3303  __         horse-power  value  of  1  lb.  M.  E.  R 

^^'^^^   36  M.  E.  P.  as  shown  by  the  card. 

6846 
3423 


41*076  horse-power. 

11 


122 


THE   engineer's  HANDY-BOOK. 


The  above  cut  shows  a  section  of  the  cylinder,  piston,  and 
steam-chest  of  an  ordinary  slide-valve  engine;  a  represents  the 
cylinder ;  6,  the  piston ;  c,  the  piston-rod ;  o  o,  recesses  in  the  cylinder- 
head  ;  k  k,  steam-ports ;  /,  exhaust  cavity  in  the  valve-seat ;  n,  exhaust 
opening  in  valve-face ;  6,  valve ;  /,  valve-rod ;  d  d,  steam-chest;  m, 
bonnet  of  steam-chest,  and  h  h,  clearance. 

The  term  clearance  is  understood  by  engineers  to  mean  the  un- 
occupied space  between  the  piston-  and  cylinder-heads  when  the 
crank  is  at  the  dead-centre;  but  it  also  applies  to  the  space  be- 
tween the  cylinder  and  the  face  of  the  valve  or  valves,  either 
slide  or  poppet.  The  amount  of  clearance  of  any  engine  affects 
its  economy ;  and  if  the  clearance  is  small,  the  engine  will  be  more 
economical  than  if  large ;  a  certain  amount  is  an  absolute  neces- 
sity. It  is,  therefore,  an  object  of  importance,  in  point  of  economy,, 
to  have  the  valve-face  as  near  the  base  of  the  cylinder  as  possible. 
In  this  lies  one  of  the  most  important  features  of  the  Buckeye, 


THE   engineer's  IIANDY-BOOK. 


123 


Brown,  Putnam,  Woodruff  and  Beacli,  etc.,  and,  in  fact,  all  en- 
gines of  the  Corliss  type.  The  clearance  varies  with  different 
builders,  and  in  different  engines  from  1^  to  10  per  cent,  of  the 
cubic  contents  of  the  cylinder. 

The  clearance  is  often  as  high  as  fifteen  per  cent.,  in  some  old- 
fashioned  long  stroke,  slide-valve  engines.  This  arose  from  a  mis- 
conception, at  the  time  they  were  designed,  of  the  waste  the  large 
clearance  would  occasion,  and  is,  perhaps,  in  many  instances,  due 
to  the  caprice  of  the  inventor  of  some  patent  piston,  who  made  his 
piston-rings  of  less  depth  than  the  original  designs,  thus  increasing 
the  space  between  the  piston-  and  cylinder-heads,  when  the  crank 
is  at  the  dead-centre.  There  are  even  cases  to  be  met  with,  where 
the  old  fashioned,  hemp-packed  piston  has  been  replaced  by  me- 
tallic packing  of  not  more  than  half  its  depth,  without  any  means 
being  taken  to  fill  up  the  spaces  at  each  end  of  the  cylinder. 
Now,  providing  that  the  clearance  is  fifteen  per  cent,  of  the  cubic 
contents  of  the  cylinder,  and  that  the  engine  makes  from  one 
hundred  and  fifty  to  two  hundred  strokes  per  minute  for  ten 
hours,  it  may  easily  be  seen  how  enormous  the  waste  must  be. 
The  quantity  of  fuel  that  might  be  saved  by  replacing  such  an 
engine  by  one  in  which  the  clearance  would  be  reduced  to  a  mini- 
mum, would  more  than  pay  for  the  latter  in  five  years.  Persons 
employing  steam-power,  or  intending  to  purchase  steam-engines, 
should  pay  attention  to  the  foregoing  fact. 

As  the  clearance  space  is  generally  irregular  in  form,  particu- 
larly in  slide-valve  engines,  it  is  somewhat  difficult  to  calculate 
the  exact  cubic  space.  The  most  accurate  method  of  ascertaining 
the  exact  aniiount  of  the  clearance  is  to  place  the  crank  at  the 
dead-centre,  and  fill  the  space  with  water  up  to  the  face  of  the 
valve  (the  quantity  of  water  being  previously  weighed  or  meas- 
ured). Then  deduct  the  amount  remaining  in  the  vessel  from  the 
whole,  and  the  remainder  will  be  the  quantity  contained  in  the 
clearance  in  cubic  inches  or  gallons,  as  the  case  may  be. 


124 


THE   ENGINEER'S  HANDY-BOOK. 


The  Woodrulf  &  Beach  Automatic  Ciit-OflF  High-Pressure 

Engine. 

The  cut  on  the  opposite  page  represents  the  Woodruff  &  Beach 
high-pressure  automatic  cut-off  engine.  Fig.  1  shows  a  section  of 
the  cylinder-valves,  steam  passages,  and  exhaust  passages.  Fig.  2 
is  a  back  view  of  the  cylinder,  steam-chests,  valve-gear,  etc.  With 
the  exception  of  the  Corliss,  it  is  the  oldest  variable  cut-off  engine 
in  the  country,  and  one  that  has  undergone  fewer  changes  in  its 
mechanism  than  any  other.  Those  who  remember  it  thirty  years 
ago,  will  fail,  at  the  present  day,  to  discover  much  difference  from 
its  general  appearance.  For  more  than  a  quarter  of  a  century  it 
has  successfully  competed  with  such  engines  as  the  Corliss,  and  it 
has  always  sustained  a  high  rating  in  the  scale  of  comparative 
merit.  The  bed-plate,  as  will  be  observed,  is  of  the  ordinary  box 
O.  G.  pattern,  to  which  the  cylinder-guides  and  pillow-blocks  are 
bolted  and  dowelled  in  such  a  manner  that  the  possibility  of  their 
getting  out  of  line  is  entirely  obviated. 

The  steam-valves,  which  are  of  the  double  poppet  form  with 
bevelled  feces  and  seats,  are  located  at  the  back  of  the  cylinder  at 
each  end,  horizontal  with  its  axis.  Their  stems  project  inward, 
and,  owing  to  the  peculiar  shape  of  the  cam  which  gives  the 
motion,  the  opening  and  closing  is  done  very  quickly  and  almost 
noiselessly.  They  have  independent  adjustments,  so  that  the 
steam  lead  may  be  varied  to  meet  any  requirement  without  inter- 
fering with  the  rest  of  the  valve-gear.  The  power  required  to 
work  the  valves  in  these  engines  is  very  slight,  and  as  the  cam- 
lug  and  the  ends  of  the  valve-stems  are  made  of  hardened  steel, 
they  show  no  perceptible  sign  of  wear  after  years  of  use. 

The  exhaust-valve,  which  is  cylindrical  in  form  and  has  a  very 
convenient  arrangement  for  taking  up  the  wear  and  preventing 
leakage,  is  placed  at  the  bottom  of  the  cylinder,  and  communi- 
cates with  it  by  its  own  ports  or  passages,  which  are  entirely  sepa- 
rate from  those  of  the  steam-valve.  An  equilibrium  of  pressure 
is  maintained  by  the  exhaust  taking  place  through  the  interior 


THE  ENGINEER^S  HANDY-BOOK. 


11* 


THE   engineer's  HANDY-BOOK. 


of  the  valve,  and  as  its  stroke  is  very  short,  the  liability  to  wear 
is  slight.  Its  motion  is  derived  from  a  transverse  shaft  under  the 
centre  of  the  guides,  carrying  an  eccentric,  and  driven  by  bevel- 
gears.  Owing  to  the 
position  of  the  ex- 
haust openings  at 
the  bottom  of  the 
cylinder,  and  their 
ample  size,  the  ex- 
haust is  very  free; 
the  discharge  of  any 
water  that  may  ac- 
cumulate from  con- 
densation or  from 
priming  in  the  boil- 
ers is  rendered  easy, 
and  all  danger  of 
accident  from  this 
cause  is  obviated. 

The  governor, 
which  is  very  pow- 
erful and  sensitive, 
and  of  a  kind  that 
is  admirably  adapt- 
ed to  these  engines, 
is  located  centrally 
between  the  steam- 
valves,  and  receives 
its  motion  from  a 
longitudinal  shaft, 
supported  on  bear- 
ings attached  to  the 
bed-plate,  and  driven  by  a  spur  and  bevel-gear  from  the  crank- 
shaft. Its  spindle  passes  through  a  compound  eccentric  carrying 
a  movable  cam-lug,  which,  by  its  rotation,  gives  the  opening  or 


THE   ENGINEEr\s  HANDY-BOOK. 


127 


outward  motion  to  the  valves,  in  which  direction  it  is  positive; 
while  the  closing,  although  controlled  by  the  cam,  is  effected  by 
the  pressure  of  the  steam  upon  the  unbalanced  area  exposed  at 
the  outer  end,  and  is 
assisted  by  a  spiral  ||rrri 
spring.  In  the  bore 
of  the  inner  eccen- 
tric is  an  inclined  or 
spiral  slot  for  the  re- 
ception of  a  key  at* 
tached  to  the  gov- 
ernor-spindle, from 
which  the  eccentric 
receives  its  motion. 
As  the  key  is  raised 
or  lowered  by  the 
variations  of  the 
governor,  the  inner 
eccentric  is  turned 
to  the  right  or  to 
the  left,  and  the 
cam-lug  moved  in 
or  out,  as  the  case 
may  be,  thereby 
giving  the  neces- 
sary opening  to  the 
valve,  and  cutting 
off  the  steam  at  the 
right  point  to  allow 
of  the  proper  de- 
gree of  expansion. 
As  the  cam-lug  is 
at  all  times  in  the 


Fig. 


same  relative  position  to  the  outer  shell  of  the  eccentric,  the  lead 
of  the  steam-valve  is  not  affected  by  the  variations. 


128  THE   ENGINEER'S  HANDY-BOOK. 

The  expansion-gear  of  these  engines  is  oneof  the  most  ingenious, 
simple,  and  effective  mechanical  devices  that  can  be  employed  for 
that  purpose.  Its  operation  may  be  explained  as  follows:  The 
cam,  marked  (7,  Fig.  3,  cuts  off  the  steam  with  certainty  at  any 
part  of  the  stroke,  the  motion  being  produced  automatically  by 
the  action  of  the  governor  upon  it,  throwing  it  more  or  less  out 
of  centre  with  the  spindle  of  the  governor ;  the  rotation  of  the 
balls  being  more  or  less  rapid,  the  eccentricity  of  the  cam  deter- 
mines the  amount  of  steam  admitted  to  the  cylinder.  To  produce 
this  effect  the  cam  is  made  of  two  pieces.    C4s  a  hollow  shell  or 


Fig.  3. 


cylinder,  with  a  part  of  one  end  formed  into  a  cam  proper. 
Throughout  the  whole  length  of  this  piece,  upon  the  inside,  there 
is  a  spiral  groove  cut  to  receive  one  end  of  a  feather,  by  which  its 
pitch  or  eccentricity  is  regulated.  The  inside  piece,  D,  (Fig.  4)  is 
a  hub  which  exactly  fits  into  the  hollow  of  the  cylinder,  C,  and  has 
a  socket,  e,  into  which  the  spindle  of  the  governor  is  secured,  the 
other  end,  d,  forming  a  journal  or  bearing  with  a  bevel-w^heel  on 
its  extremity,  to  transmit  the  motion  from  the  crank-shaft  gearing 
to  the  governor  and  cut-off.  There  is  a  hole  throughout  the  length 
of  the  inside  piece,  D,  which  is  continued  through  the  spindle  of 
the  governor,  and  which  contains  the  rod  which  connects  the  cam 
with  the  governor.  This  hole  is  eccentric  to  the  outside  surfaces 
of  D  and  C,  but  is  concentric  with  the  collar,  /,  and  with  the 
governor-rod.  Both  pieces,  C  and  D,  are  connected  by  a  feather, 
one  piece  of  which  is  of  a  spiral  form,  and  the  other  straight;  the 


THE   ENGINEER\s    HANDY-ROOK.  129 

two  being  connected  together  by  a  stub  which  fits  into  a  hole  or 
bearing  in  the  spiral  piece,  so  that  the  latter  can  turn  on  the  stub 
and  accommodate  itself  to  the  groove  in  which  it  works.  The 
spiral  part  of  the  feather  works  in  a  spiral  groove  in  the  inside 
of  the  shell,  C,  and  the  rectangular  piece  works  in  a  straight 
groove  on  the  inside  of  the  hub,  />,  the  inner  part  of  the  rectan- 
gular piece  being  fastened  to  the  governor-rod,  so  that  the  feather 
is  permanently  connected  with  the  governor.  When  the  several 
pieces  are  put  together  the  cam  is  complete,  as  shown  in  Fig.  4, 
and  it  operates  as  follows :  Motion  is  communicated  by  gearing 
from  the  crank-shaft  to  the  bevel-wheel  on  the  end  of  the  piece, 


Fig.  4. 


/),  as  well  as  to  the  spindle  of  the  governor,  which  is  screwed  into 
the  socket  on  D;  as  the  balls  rise  or  fall  through  change  in  the 
centrifugal  force,  due  to  the  variation  in  the  speed  of  rotation, 
they  raise  or  depress  the  governor-rod,  which  passes  through  the 
spindle,  and  the  piece,  D,  which  is  attached  to  the  feather  thereby 
raising  or  depressing  it.  This  feather  acting  on  the  spiral  groove 
instantly  alters  the  lift  of  the  cam,  and  regulates  the  amount  of 
steam  admitted  to  the  cylinder.  By  these  means  any  speed  may 
be  selected  at  which  the  load  of  the  engine  is  to  move,  and  any 
variation  from  that  will  be  instantly  felt  by  the  governor,  and  cor- 
rected. There  is  no  jar  in  the  working  of  the  parts;  the  feather 
moves  noiselessly  in  its  grooves ;  the  governor-rod  moves  up  and 
down  through  the  spindle  and  the  piece  D,  and  can  be  regulated 
to  give  any  required  opening  of  the  steam-ports  to  suit  the  work 
to  be  done, 

I 


130 


THE   engineer's  HANDY-BOOK. 


The  Woodruff  &.  Beach  engines  are  very  simple  in  design,  and 
have  the  reputation  of  being  very  durable  and  economical.  Ab- 
sence of  complication  in  the  valve-motion,  and  the  ease  with  which 
all  the  w^orking  parts  can  be  adjusted,  are  valuable  features. 

Automatic  Cut-Off  and  Throttling  Engines. 

All  steam-engines,  for  whatever  purpose  designed  or  em- 
ployed, are  either  automatic  cut-off  or  throttling.  In  the  auto- 
matic cut-off  engines,  the  steam-valves  are  so  controlled  by  the 
governor,  as  to  cut  off  the  steam  at  any  point  from  zero  to  three- 
quarter  stroke  —  the  cut-off  taking  place  earlier,  or  later,  to  accom- 
modate the  varying  load  on  the  engine  and  the  pressure  in  the 
boiler,  the  object  being  to  obtain  full  boiler  pressure  at  the  com- 
mencement of  each  stroke,  and  maintain  it  to  the  point  of  cut-off, 
leaving  the  balance  of  the  stroke  to  be  completed  by  expansion, 
the  speed  of  the  engine  being  controlled  by  the  cut-off  and  not  by 
throttling.  In  engines  of  this  class,  there  is  no  impediment  (save 
such  as  may  occur  at  the  port  of  entrance)  to  the  free  flow  of 
steam  from  the  boiler  to  the  cylinder,  the  regulation  being  effected 
not  by  diminishing  the  pressure,  but  by  cutting  off  in  the  cylinder  , 
the  volume  of  steam  necessary  for  each  particular  stroke;  conse- 
quently, the  only  loss  in  pressure  between  the  boiler  and  the  cyl- 
inder is  that  due  to  the  number  of  bends,  and  the  length  of  the 
connecting  pipe. 

Although  all  intelligent  engineers  are  agreed  upon  the  superior 
economy  of  the  automatic  cut-off  engine,  few,  excepting  those  who 
have  had  the  opportunity  of  making  a  practical  comparison,  are 
aware  of  the  great  saving  in  the  expense  of  fuel  over  that  class 
of  engines  wherein  the  point  of  cut-off  is  invariably  relative  to 
the  stroke  of  the  piston.  It  is  well  understood,  that  the  amount 
of  work  realized,  as  compared  to  the  total  theoretical  work  due 
the  volume  of  steam  expended,  even  in  the  most  perfect  engine,  is 
a  very  small  percentage  of  the  whole  energy  ;  and  it  is,  therefore, 
the  more  an  object  of  interest  to  know  precisely  what  the  differ- 


THE   engineer's  HANDY-BOOK. 


131 


ence  is  between  these  two  classes  of  engines  in  point  of  economy. 
The  conditions  which  insure  the  highest  grades  of  economy  are  a 
full  port  with  no  intervening  obstructions  to  impede  the  free  flow^ 
of  the  steam,  and  a  rapid  movement  of  the  cut-off,  or  steam-valve, 
over  the  port ;  as  mere  increase  in  the  mean  effective  pressure,  re- 
sulting from  a  tardy  closing  of  the  port,  represents  no  gain  during 
one  stroke  of  the  piston  that  may  be  stored  up  and  expended 
during  the  succeeding  stroke  ;  hence,  any  force  upon  the  piston  in 
excess  of  that  required  to  balance  the  resistance  will  result  in  a 
diminished  economy. 

The  economy  of  high-pressure  engines  is  exactly  in  propor- 
tion as  their  average  piston  pressure  is  higher  than  the  terminal, 
providing  the  latter  does  not  fall  below  that  of  the  atmosphere ; 
the  highest  economy  being  attained  when  the  stroke  is  commenced 
with  full  boiler-pressure,  and  the  steam  quickly  and  completely 
cut  off,  at  a  point  in  the  stroke  that  allows  the  pressure  to  fall  to, 
or  very  near,  that  of  the  atmosphere. 

Throttling  Engines. 

Throttling  engines  are  those  in  which  the  flow  of  steam  from 
the  boiler  to  the  cylinder  is  regulated  either  by  a  throttle-valve,  a 
kind  of  damper  in  the  steam-pipe,  which,  as  the  speed  of  the  en- 
gine increases,  is  turned,  and  stops  off  the  supply  of  steam,  or  by 
the  steam  in  its  passage  from  the  boiler  to  the  cylinder  oozing 
through  the  passage  of  some  peculiar  type  of  governor- valve. 
An  engine  controlled  by  any  such  device  is  in  a  condition  some- 
what like  that  of  a  horse  restrained  by  a  brake  applied  to  the 
wheels  of  a  wagon.  Such  relics  of  barbarism  are  fast  giving  place 
to  the  automatic  cut-off  arrangement,  by  which  the  brakes  are 
removed  from  the  wheels,  and  the  bit  placed  in  the  horse's  mouth, 
instead.  Manufacturers  of  this  class  of  engines  claim  that  they 
give  results  equal  to  the  automatic  cut-off  engines,  which  is  un- 
true, both  as  to  economy  and  close  governing.  With  an  early  cut- 
off, which  is  absolutely  necessary  to  good  economy,  it  is  simply 


132  THE   ENGINEER'S  HANDY-ROOK. 


impossible  to  govern  the  speed  of  throttling  engines  closely,  with 
even  a  moderate  change  in  load  and  pressure. 

In  the  best  types  of  throttling  engines,  in  consequence  of  the 
peculiar  construction  of  the  governor-valve,  and  the  tortuous  pas- 
sage through  which  the  steam  has  to  travel,  the  pressure  in  the 
cylinder  is  in  many  cases  not  more  than  one-half  of  the  boiler  press- 
ure ;  the  effect  of  which  is,  that  when  the  work  to  be  performed  is 
varying  in  its  nature,  such  engines  increase  their  speed  when  any 
considerable  load  is  thrown  off,  and  decrease  it  when  additional 
load  is  put  on.  Now,  every  stroke  an  engine  makes  above  its 
regular  speed  is  a  waste  of  steam,  and  if  the  engine  is  large,  or 
runs  at  a  high  speed,  the  volume  of  steam,  and  consequently  of 
fuel,  wasted  will  be  enormous ;  likewise  every  stroke  an  engine 
makes  below  its  ordinary  speed,  when  work  is  thrown  on,  lessens 
production.  The  loss  of  one  revolution  in  ten  diminishes  the  pro- 
ductive capacity  of  every  machine  driven  by  the  engine  10  per 
cent. ;  in  short,  the  loss  of  one  revolution  in  ten  diminishes  the 
productive  capacity  of  the  whole  factory  10  per  cent. ;  while  the 
expense  of  conducting  the  whole  business,  rent,  wages,  insurance, 
etc.,  continues  the  same  as  if  everything  was  in  uniform  motion. 
A  variation  of  one  revolution  in  ten  is  quite  common  in  throttling 
engines :  in  fact,  it  is  unavoidable. 

Steam-Engine  Cut-Oflfs. 

The  great  desideratum  in  the  use  of  steam  is  the  most  perfect 
application  of  the  expansive  principle.  As  the  pressure  of  steam 
is  always  calculated  in  pounds  per  square  inch  above  atmospheric 
pressure,  the  nearer  the  indicated  line  of  expansion  approaches 
that  of  the  atmosphere,  the  greater  is  the  actual  power  derived 
from  the  utilized  volume  of  steam.  Were  the  boiler  pressure  and 
th.e  load  or  resistance  on  an  engine  always  uniform,  it  would  be 
an  easy  matter,  by  making  the  cylinder  of  the  necessary  dimen-  ' 
sions,  to  set  the  cut-off  at  the  proper  point  for  allowing  of  proper  j 
expansion.    As,  however,  the  pressure  and  load  are  constantly 


THE   engineer's  HANDY-BOOK. 


133 


varyiDg,  it  is  necessary  to  reduce  the  consumption  of  steam  to  a 
minimum  which,  by  its  perfect  expansion,  will  give  the  required 
power.  To  these  considerations  may  be  attributed  the  efforts 
which  have  resulted  in  the  adoption  of  the  three  devices  now  in 
use,  viz.,  the  positive,  adjustable,  and  variable,  or  automatic  cut-offs. 

In  the  positive  cut-off  the  expansion  of  steam  is  effected  by  what 
is  known  as  lap  on  the  valve,  by  which  the  steam  is  cut  off  at  the 
same  point  in  each  stroke,  independent  of  load  or  pressure ;  al- 
though in  some  instances  the  expansion  of  steam  in  the  cylinder 
is  effected  by  an  independent  cut-off  riding  on  the  back  of  the 
main  valve,  and  receiving  its  motion  from  an  eccentric.  Such  an 
arrangement,  like  the  former,  is  productive  of  beneficial  results ; 
but  nevertheless  it  is  very  defective,  inasmuch  as  it  is  stationary, 
and  cannot  be  varied  to  meet  the  requirements  of  work,  pressure, 
and  speed. 

In  the  adjustable  cut-off  the  expansion  is  effected  by  an  inde- 
pendent valve,  which  can  be  adjusted  by  the  engineer,  outside  of 
the  steam-chest,  by  means  of  a  screw,  hand-wheel,  or  other  me- 
chanical arrangement  to  meet  the  requirements  of  work  and 
pressure.  The  link,  in  its  application  to  the  steam-engine,  belongs 
to  this  class  of  cut-offs.  Although  such  arrangements  are  adjust- 
able, they  are  not  self-adjusting,  and  when  once  set  will  cut-off 
independent  of  circumstances. 

The  variable  or  automatic  cut-off  performs  its  functions  accord- 
ing to  circumstances  of  load  and  pressure,  both  in  admitting  and 
cutting  off  the  steam.  It  gives  regularity  of  motion  and  secures 
all  the  benefits  of  expansion,  as  the  governor  operates  the  mechan- 
ism which  determines  the  exact  point  in  the  stroke  where  the 
supply  of  steam  from  the  boiler  should  be  cut  off  and  expansion 
begin.  This  insures  the  most  perfect  regulation  under  the  most 
varying  circumstances,  as  the  slightest  change  in  the  position  of 
the  governor  will  increase  or  decrease  the  initial  charge  of  steam 
admitted,  thus  balancing  any  variation  in  the  amount  of  resist- 
ance. It  must  not  be  inferred  from  the  foregoing  that  any  me- 
chanical arrangement  that  may  be  termed  by  its  inventor  an  auto- 
12 


134 


THE   ENGINEER'S  HANDY-BOOK. 


matic  cut-off  is  capable  of  producing  economical  results,  as  many 
of  them  are  nothing  but  rattle-traps,  undeserving  of  the  name  of 
automatic  cut-offs. 

The  cut-offs  most  generally  used  on  steam-boats,  tugs,  and  fer- 
ries, are  either  the  Stevens,  Sickles,  or  Winters.  They  all  receive 
their  motion  from  an  eccentric  on  the  main  shaft.  The  Stevens 
cut-off  has  two  rock-shafts, —  one  for  the  steam  and  one  for  the  ex- 
haust,— which  are  operated  by  two  separate  eccentrics.  The  Sickles 
cut-off  is  operated  by  an  eccentric,  the  valves  being  tripped  by  a 
wedge,  so  arranged  as  to  disengage  the  valve-gear  at  any  point  of 
the  stroke.  Dash-pots  are  employed  to  ease  the  valves  into  their 
seats.  The  Winters  cut-off  is  operated  by  a  revolving  shaft,  which 
receives  its  motion  from  an  eccentric.  One  of  the  advantages  of 
this  cut-off  is  that  it  can  be  arranged  to  cut  off  at  any  desired 
point  of  the  stroke  when  the  engine  is  in  motion,  but  neither  the 
Stevens  nor  the  Sickles  can.  Zachariah  Allen,  of  Providence, 
R.  I.,  was  undoubtedly  the  inventor  of,  and  the  first  to  practically 
apply,  the  automatic  cut-off,  which  is  unquestionably  one  of  the 
greatest  improvements  ever  made  in  the  steam-engine. 

Design  of  Steam-Engines. 

The  design  op  improvement  of  any  class  of  machinery  must 
be  based  upon  two  suppositions,  either  that  existing  mechanism  is 
impej^fect  in  its  construction,  or  that  it  lacks  functions  which  a 
new  design  may  supply.  In  most  cases  it  would  seem  that  any 
machine,  or  part  thereof,  is  susceptible  of  improvement;  yet  it  will 
be  generally  found  no  easy  matter  to  hit  upon  a  design,  or  con- 
ceive a  plan,  to  remedy  the  existing  fault.  Therefore  no  person 
should  undertake  to  design  a  machine  unless  he  is  well  acquainted 
with  the  principles  involved  in  working  it.  He  should  be  able 
to  calculate  strength,  strains,  and  forces,  and  apply  the  calcula- 
tions so  as  to  apportion  the  quantity  and  form  of  the  material  in 
the  various  parts  of  the  machine,  in  order  to  produce  the  greatest 
amount  of  strength  with  the  least  expenditure  of  material.  Bo- 


THE   engineer's  HANDY-BOOK. 


135 


«fdes  a  design  may  be  based  on  right  principles,  and  yet  unfore- 
seen mechanical  difficulties  may  prevent  its  application;  it  may 
introduce  complication  of  parts,  incur  extra  expense,  or  not  be 
susceptible  of  convenient  or  easy  adjustment.  The  fewer  the 
parts,  and  the  more  harmonious  the  action,  the  more  valuable  the 
machine  will  be,  providing  it  embodies  a  good  principle  in  its 
design. 

Before  any  correct  formulaB  by  which  to  determine  the  proper 
proportions  for  steam-engines  can  be  deduced,  there  are  many 
things  to  be  considered,  such  as  permanent  load,  weight  of  mov- 
ing material,  nature  of  motion,  etc.  The  load  on  the  piston-rod 
consists  of  the  piston  at  one  end,  and  the  cross-head  at  the  other; 
consequently  the  greater  the  length  between  these  two  points  the 
more  the  rod  is  affected.  For  this  reason,  it  is  obvious  that,  when 
it  becomes  necessary  to  determine  the  area  of  the  piston-rod,  the 
pressure  area  of  cylinder  load  and  length  of  travel  must  be  duly 
considered.  The  connecting-rod  being  hung  between  a  sliding  and 
a  rotary  motion,  the  load  is  in  some  measure  due  to  the  length  of 
the  rod  in  proportion  to  the  circle  described.  In  the  first  case,  the 
sliding-point  has  a  load  on  it  due  to  the  weight  of  the  piston-rod, 
beyond  the  stuffing-box,  with  the  additional  weight  of  the  cross- 
head.  In  the  second  instance,  the  rotating  surface  is  affected  by 
the  weight  of  the  rod  and  that  of  the  crank. 

To  determine  the  diameter  of  the  crank-shaft  we  must  take 
into  account  the  weight  of  the  crank  as  a  lever,  and  the  pressure 
of  steam  as  the  weight  on  the  end  of  the  same.  The  proportions 
of  the  crank-pin  are  likewise  modified  according  to  pressure,  per- 
manent load,  length  of  stroke,  shearing  strain,  etc. 

The  most  valuable  features  of  a  steam-engine  are  strength, 
durability,  simplicity,  fewness  of  parts,  and  easy  and  convenient 
arrangements  for  the  adjustment  of  its  working  parts;  as  its 
economy  will  depend  on  the  harmonious  action  of  its  reciprocat- 
ing and  revolving  mechanism,  as  well  as  on  the  nature  of  the 
material  and  the  excellence  of  the  workmanship  employed  in  its 
construction. 


136  THE   ENGINEER'S  HANDY-BOOK. 

Duplicating  the  Parts  of  Steam-Engines. 

Duplicating  the  parts  of  any  class  of  machines  is  an  advantage, 
as  it  insures  more  uniform  proportions  in  their  original  construc- 
tion than  could  otherwise  be  obtained,  as  the  term  duplication 
of  parts  conveys  the  impression  that  they  are  made  to  standard 
gauges,  and  for  any  number  of  machines  must  retain  the  propor- 
tions of  the  original.  While  duplication  of  parts  is  convenient, 
and  sometimes  of  great  value  in  cases  of  emergency,  it  is  rarely 
so  in  case  of  repairs ;  since,  as  soon  as  any  journal  or  bearing  is 
put  into  use,  its  dimensions  begin  to  change,  the  cylinder  com- 
mences to  enlarge  and  the  piston  to  diminish.  This  change  of 
shape  extends  to  the  piston-rod,  and  glands  of  the  stuffing-boxes, 
wrist-pins,  crank-pins,  rocker-shafts,  etc.  The  eccentric  wears  flat 
on  two  sides,  in  consequence  of  the  thrust  at  these  points,  and  the 
straps  wear  flat,  owing  to  the  push  and  pull  at  two  points. 

Now  how  can  it  be  expected  that  a  new  eccentric  will  fit  the 
old  straps,  or  the  new  straps  conform  to  the  old  eccentric,  or  that 
the  new  piston  will  prove  a  good  fit  for  the  old  cylinder,  or  the 
new  piston-rod  for  the  worn-out  gland  ?  If  the  crank-shaft  be- 
comes worn  oval,  it  will  not  adjust  itself  to  a  new  main-bearing 
made  from  the  original  standard  ;  or  if  the  crank-pin  becomes  worn 
tapering,  owing  to  the  engine  being  out  of  line,  a  box  made  of  the 
original  proportions  will  not  drop  into  its  place  and  work  har- 
moniously ;  but,  as  before  stated,  in  case  of  emergency,  such  as 
break-downs,  or  where  interruption  to  business  would  entail  great 
loss,  duplicate  parts  are  a  tolerably  good  make-shift,  and  that  is 
all  that  can^be  said  in  their  favor.  For  this  reason,  the  duplica- 
tion of  parts,  which  in  case  of  breakage  would  be  most  likely  to 
disable  a  machine,  ought  to  be  encouraged,  especially  in  case  of 
marine  engines,  locomotives  running  in  sections  of  the  country 
where  there  are  no  repair  shops,  and  stationary  engines  located 
in  isolated  places. 


THE   engineer's  HANDY-BOOK. 


137 


Fitting  the  Cranks  of  Steam-Engines  to  their  Shafts. 

Boring  the  hole  for  the  shaft  in  the  crank  is  not  so  easy  a  task 
as  the  average  engineer  would  suppose.  Theoretically,  when  the 
hole  is  bored  in  the  crank,  if  the  boss  is  faced  true,  and  then  bolted 
to  a  true  face-plate  on  a  lathe,  it  must  be  true.  But  inaccuracy 
frequently  arises  from  the  fact  that  there  are  few  face-plates  whi(;h 
are  true,  and  continue  to  remain  so  for  any  length  of  time.  And 
even  when  the  boring  is  as  well  done  as  can  be  expected  under 
the  circumstances,  the  crank  is  frequently  thrown  out  of  line  in 
keying  it  on  the  shaft.  For  this  reason,  no  crank  should  leave 
the  works  where  it  was  made  without  being  tested  after  having 
been  keyed  on. 

When  the  crank  is  in  the  form  of  a  disc,  or  wheel,  the  best 
plan  is  to  turn  it  true,  first  on  a  mandril,  and  then  so  fit  it  to  the 
shaft,  and  the  key  to  its  seat,  that  after  the  keying  it  will  run 
true ;  but  with  the  ordinary  crank,  this  cannot  be  so  easily  done, 
as  all  the  surface  available  for  testing  its  truth  is  near  the  centre ; 
in  such  cases,  the  main  reliance  must  be  placed  in  fitting  the  key  as 
well  as  the  crank  itself  to  the  shaft.  The  key  should  never  be  finally 
driven  till  it  has  first  been  frequently  partially  driven,  its  points 
of  contact  filed  or  scraped,  and  it  fits  perfectly  its  whole  length. 

The  essential  conditions  necessary  for  the  production  of  a  well- 
fitting  and  durable  crank-shaft  journal  are,  good  material,  a  stiflT, 
strong  lathe,  a  skilful  machinist,  and  a  sharp,  well-tempered,  and 
correctly  set  tool.  The  finishing  cuts  should  be  light,  and,' if  it 
cannot  be  made  suflSciently  smooth  with  the  tool,  it  must  not  be 
filed,  but  may  be  ground  and  polished  smooth  by  blocks  of  wood, 
lead,  copper,  or  some  other  suitable  material  fitted  to  the  journal 
in  such  a  manner  that  the  imperfections  left  by  the  turning-tool 
will  be  corrected  instead  of  aggravated  by  the  use  of  a  file  or  end 
of  a  stick,  as  is  commonly  the  case.  The  polishing  powder  used 
should  be  very  fine ;  emery  is  considered,  by  many,  objectionable  for 
polishing  wearing  surfaces,  but  on  good  homogeneous  material,  free 
from  flaws,  fine  emery  may  be  used  without  any  injurious  efl'ect'^ 

1  O  -it.  J  J 


138 


THE    engineer's  HANDY-HOOK. 


The  Putnam  Machine  Company's  Automatic  Cut-Off  Engine, 

The  opposite  cut  represents  the  Putnam  Machine  Company's 
high-pressure  variable  cut-off  engine,  the  frame  or  bed-plate  of 
which  is  designed  with  reference  to  strength  and  rigidity,  and  also 
to  answer  either  for  right  or  left  hand  pillow-block  bearings.  The 
almost  universal  reciprocating  valve-motion  derived  from  an  ec- 
centric is  dispensed  with,  and  a  rotary  motion  derived  from  a  gear 
on  the  crank-shaft  substituted.  By  means  of  mitre-gears  the  mo- 
tion is  communicated  to  a  shaft  running  parallel  with  the  axis  of 
the  cylinder  beneath  the  valves,  and  carrying  cams  for  lifting  the 
latter.  The  steam-chests,  one  at  either  end  of  the  cylinder,  contain 
each  a  steam  and  an  exhaust  valve  of  the  balance  or  double-poppet 
form,  having  flat  faces  and  seats,  and  are  capable  of  being  removed 
entire  from  the  steam-chests  by  simply  removing  a  bonnet  or  cover 
on  the  top  of  the  latter.  The  valve-stems  pass  through  the  neces- 
sary stufiing-boxes  in  the  bottom  of  the  steam-chests.  The  shape 
and  adjustment  of  the  cams  for  working  the  valves  give  them  the 
proper  lift,  lap,  lead,  etc.  The  opening  and  closing  of  the  valves 
are  very  quick,  the  duration  of  opening  being  an  interval  of  rest 
between  the  upward  and  downward  motions. 

The  governor,  which  is  of  the  ordinary  centrifugal  form,  is 
driven  by  bevel-gears  from  the  cam-shaft,  thus  receiving  a  positive 
motion.  Below  the  cam-shaft  is  a  rack-shaft  having  three  arms, 
the  centre  one  of  which  is  attached  to  the  lifting-rod  or  spindle 
of  the  governor,  from  which  the  rack-shaft  receives  a  slight  oscil- 
lating motion,  while  those  at  the  ends,  which  are  at  right  angles 
with  the  centre  arm,  connect  with  the  lifting  toes  of  the  steam- 
valve.  The  shape  of  the  lower  faces  of  the  lifting  toes  which  rest 
upon  the  cams  is  such,  that  when  moved  inward  towards  the  cyl- 
inder, by  the  motion  of  the  governor  transmitted  through  the 
rack-shaft,  a  curved  upward  offset  is  reached  by  the  cam  as  it  re- 
volves, and  the  valve  is  lowered  so  quickly  as  to  have  the  effect 
of  being  actually  released  and  allowed  to  drop  to  its  seat,  while  at 
the  same  time  it  is  supported  by  the  lifter.    The  interval  between 


THE   ENGINEER'S  HANDY-JiOOX. 


140 


THE   ENGINEER'S  HANDY-BOOK. 


the  full  lift  of  the  valve  and  the  reaching  of  the  offset  by  the 
highest  point  of  the  cam  determines  the  point  of  cut-off,  and  in- 
sures sufficient  lift  of  the  valves.  The  advantage  claimed  for  this 
arrangement  is,  that  by  keeping  the  valve  always  supported  while 
open,  the  danger  of  slamming  is  avoided  without  the  necessity  of 
a  dash-pot,  which,  in  cases  where  the  valve  is  tripped  or  released, 
is  absolutely  indispensable. 

When  these  engines  are  started,  and  until  the  speed  for  which 
the  governor  is  adjusted  is  reached,  the  steam  necessarily  follows 
full  stroke,  as  the  cut-off  is  inoperative.  But  as  soon  as  the  reg- 
ular speed  is  attained,  the  motion  of  the  governor  thrusts  the 
centre  arm  of  the  rack-shaft  downward,  thereby  causing  the  arms 
to  which  the  lifting  toes  are  connected  to  move  towards  the  cyl- 
inder. This  brings  the  offsets  of  the  lifting  toes  nearer  to  the 
cams,  causing  them  to  drop  sooner,  thus  cutting  off  the  steam  at 
the  proper  point.  In  case  of  the  removal  of  the  entire  load  from 
the  engine,  induced  by  the  breaking  of  a  belt,  etc.,  the  governor, 
owing  to  its  positive  motion,  will  effectually  check  any  attempt  at 
"  running  away,"  as  the  offsets  on  the  lifting  toes  will  be  thrust  so 
far  inward,  that  the  cams  will  not  raise  the  valves  from  their  seats 
until  the  speed  is  again  reduced  to  the  proper  point. 

It  is  claimed  that,  under  the  above-mentioned  circumstances,  the 
engine  will  not  make  one  full  revolution  before  being  completely 
under  the  control  of  the  governor.  All  the  sliding  and  bearing 
surfaces  of  the  valve-gear  of  these  engines  are  made  of  hardened 
steel,  thus  preventing  the  liability  of  rapid  wear,  and  also  requir- 
ing very  little  power  to  move  the  valves.  The  fly-wheels  are 
turned  on  the  face  and  edges.  The  shafts,  crank-pins,  and  con- 
necting-rods are  made  of  the  best  material,  and  the  bearings  are 
ample  and  well  proportioned.  The  workmanship  is  excellent,  and 
the  finish  neat  and  attractive.  In  fact,  these  engines  rank  among 
the  most  simple,  durable,  and  economical  in  the  country.  They 
are  manufactured  by  the  Putnam  Machine  Company,  Fitchburg, 
Mass. 


THE   ENGTNFI<^r's    H  A  N  T)  Y  -  B  T)  O  K  . 


141 


How  to  put  ail  Eii^^iiie  in  Line. 

An  engine  is  in  line  when  the  axis  of  the  cylinder  and  the 
piston-rod  are  in  one  and  the  same  straight  line  in  all  positions. 
This  line  extended  should  intersect  the  axis  of  the  engine-shaft, 
and  be  at  right  angles  to  it.  The  guides  should  also  be  parallel 
thereto.  The  shaft  must  be  level,  but  the  centre  line  of  the  cyl- 
inder may  be  level,  inclined,  or  vertical,  according  to  the  design 
of  the  engine. 

To  "  line  up  "  an  engine,  as  it  is  generally  termed,  take  off 
the  cylinder-head,  remove  the  piston,  cross-head,  and  connecting- 
rod  ;  then  with  a  centre  punch  make  four  (4)  marks  in  the  counter- 
bore  at  each  end  of  the  cylinder,  at  equal  distances  apart  round 
the  bore.  Take  a  piece  of  stiff  hoop-iron  with  a  hole  at  one  end 
of  it,  slip  it  on  to  one  of  the  stud-bolts  of  the  back  cylinder-head, 
and  secure  it  firmly  with  a  nut,  after  which  it  may  be  bent  in  the 
shape  of  a  crank,  one  end  projecting  across  the  cylinder  at  its 
centre,  at  a  sufficient  distance  from  it  to  admit  of  convenient  and 
accurate  measurement.  Next  draw  a  fine  line  through  the  cylin- 
der, and  attach  one  end  of  it  to  the  temporary  crank  above  men- 
tioned, and  the  other  end  to  a  stake  driven  into  the  floor  at  the 
back  end  of  the  bed-plate.  Then  with  a  piece  of  hard  wood  or 
stiff  wire  pointed  at  each  end  and  equal  in  length  to  half  the 
diameter  of  the  cylinder,  set  the  line  so  that,  when  one  point  of 
the  wood  or  wire  is  inserted  in  any  one  of  the  centre-punch  marks 
at  either  end  of  the  cylinder,  the  other  end  will  feel  the  line.  Next 
see  if  this  line  passes  through  the  centre  of  the  shaft ;  if  so,  the 
cylinder  is  in  line  with  the  shaft ;  if  not,  one  or  the  other  must 
be  moved,  which  requires  both  skill  and  judgment,  since  engines 
differ  so  much  in  design  and  construction.  Now  turn  the  engine- 
shaft  round  till  the  crank-pin  almost  touches  the  line  passing 
through  the  centre  of  the  cylinder ;  then  ascertain  by  measure- 
ment whether  the  line  is  equidistant  from  the  collars  on  the 
crank-pin.  Then  turn  the  shaft  on  the  other  centre  until  the 
crank-pin  feels  the  line.    If  the  measures  correspond,  the  shaft 


142 


THE   engineer's  HANDY-BOOK. 


is  in  line  with  the  cylinder;  if  not,  they  will  show  which  end 
needs  to  be  moved.  The  operation  may  have  to  be  gone  over 
several  times  before  a  definite  conclusion  can  be  arrived  at.  The 
shaft  may  be  levelled  by  placing  a  spirit-level  on  it,  if  there  be 
room ;  if  not,  drop  a  plumb-line  passing  through  the  centre  of  the 
crank-pin  and  shaft ;  then  by  placing  the  crank  at  both  centres 
and  at  half-stroke,  the  line  will  show  whether  the  shaft  is  level  or 
not.  The  guides  may  be  brought  into  line  with  the  cylinder,  by 
measuring  from  each  end  of  each  guide  to  the  line  passing  through 
the  centre  of  the  cylinder,  and  moving  them  until  they  are  par- 
allel to  the  line  and  to  each  other.  To  adjust  them  to  the  hori- 
zontal, a  spirit-level  may  be  placed  on  their  top  faces.  If  no  level 
is  at  hand,  a  square  and  plumb-line  may  be  used.  Where  these 
accessories  are  not  at  hand,  a  straight-edge  placed  across  them 
will  determine  by  actual  measurement  whether  they  are  in  line 
with  the  centre  line  of  the  cylinder  or  not. 

Engines  get  out  of  line  from  the  following  causes :  Faults  of 

^  design,  faults  of  construction,  overwork,  the  character  of  the  work 
which  they  are  performing,  or  from  the  boss  of  the  crank  wearing 
away  the  face  of  the  main  bearing  against  which  it  revolves.  To 
move  an  engine-shaft  and  pillow-blocks  into  line  with  the  centre 
of  the  cylinder,  screw  down  the  caps  of  the  pillow-blocks  firmly 
on  the  shaft ;  then  slack  up  on  the  bolts  that  tie  down  the  pillow- 
blocks  to  the  bed-pla*te,  after  which  the  shaft  pillow-blocks  and 
fly-wheel  may  be  moved  from  the  back  end  by  means  of  a  lever 
or  jack-screw,  after  which  they  should  be  firmly  tied  and  the  set- 

.  screws  or  wedges  readjusted.  To  move  a  cylinder,  if  the  connec- 
tions be  short  and  stiff*,  remove  the  bolts  which  tie  it  to  the  bed- 
plate ;  then  measure  from  the  flange  of  the  cylinder  to  some  fixed 
object,  such  as  a  wall,  post,  or  column  ;  cut  a  plank  or  scantling 
about  an  inch  longer  than  the  actual  measurement  from  the  cyl- 
inder to  the  wall,  so  that  when  placed  against  the  cylinder  it  may 
stand  slightly  oblique ;  then  by  driving  on  the  end  of  the  plank 
with  a  sledge  or  heavy  hammer,  the  cylinder  may  easily  be  moved. 
The  holes  should  then  be  reamed,  and  new  bolts  corresponding  to 


THE   ENGINEER\s  HANDY-BOOK. 


143 


the  reamer  substituted  for  the  old  ones.  The  cylinders,  guides, 
and  pillow-blocks  of  all  engines  should  be  double-pinned  to  pre- 
vent them  from  getting  out  of  line ;  and  whenever  it  becomes 
necessary  from  wear  to  move  them,  the  holes  may  be  re-reamed 
and  new  pins  substituted. 

How  to  Set  Up  a  Stationary  Engine. 

The  first  object  to  determine  in  setting  up  steam-engines  is  to 
decide  definitely  the  precise  point  at  which  the  engine  is  to  be 
located,  after  which  the  excavation  for  the  foundation  may  be 
made.  It  should  be  at  least  two  feet  wider  and  longer  than  the 
intended  brick-  or  stone-work,  and  its  depth  must  depebd  on  the 
size  and  weight  of  the  engine  and  character  of  the  soil.  For  ordi- 
nary sized  engines,  say  from  20  to  40  horse-power,  from  3  to  4 
feet  will  suffice,  if  the  soil  is  dry  and  firm  ;  but  if  sandy  or  swampy, 
it  will  require  to  be  sunk  deeper.  For  large  engines  of  from  50 
to  100  horse-power  it  is  necessary  to  find  a  solid  bottom.  There 
are  even  instances  where  piles  had  to  be  driven  to  insure  a  per- 
manent foundation.  Too  much  care  cannot  be  taken  in  this  par- 
ticular, as  any  defect  in  the  foundation  will  materially  affect  the 
working  of  the  engine. 

Having  decided  on  the  location  where  the  engine  is  intended  to 
stand,  line  down  from  the  side  of  the  line  of  shafting,  or  counter- 
shaft, if  there  be  any,  to  the  floor,  at  three  or  four  different  places 
in  its  length ;  but  if  there  be  no  shafting,  measure  from  the  side 
of  the  building  to  the  centre,  at  five  or  six  points  in  its  length ; 
then  strike  a  line  across  all  these  points.  This  line  will  show  with 
sufficient  accuracy  the  line  of  the  building  by  which  the  templet 
may  be  set  up  ;  the  latter,  as  shown  in  the  cut  on  page  144,  should 
be  a  fac-simile,  or  exact  counterpart  of  the  bottom  of  the  bed-plate. 
It  may  be  made  of  inch  pine  boards,  and  set  on  four  props  over 
the  excavation,  after  which  it  must  be  squared  and  levelled  with 
the  lines  previously  taken.  The  anchor-bolt^  may  now  be  hung 
in  the  templet,  and  the  bricklayers  proceed  with  their  work.  It 


144 


THE   ENGINEER'S  HANDY-BOOK. 


is  customary  to  lay  from  two  to  three  courses  of  bricks  on  the  bot- 
tom of  the  foundation  before  the  anchors  are  reached.  These  con- 
sist of  plates  of  cast-iron  or  old  boiler-plate,  generally  about  a  foot 
square,  with  a  hole  sufficiently  large  for  the  foundation  bolts  to 
slip  through  ;  though  in  some  instances  the  anchors  extend  entirely 
across  the  foundation  and  take  in  two  bolts  each. 


o 

o 

o 

o 

o 

o 

o 

o 

The  foundation  should  be  widest  at  the  bottom,  and  slope  up- 
wards about  2  inches  to  the  foot,  till  the  level  of  the  floor  is 
reached,  after  which  it  may  be  carried  up  straight.  When  fin- 
ished, it  may  be  an  inch  wider  on  each  side  and  end  than  the 
bed-plate ;  after  which  it  should  be  made  perfectly  level  by  means 
of  a  coat  of  good,  strong  mortar  or  cement.  A  parallel  piece  of 
pine  wood,  1  inch  in  diameter  and  from  3  to  4  inches  wide,  made 
perfectly  straight  on  both  edges,  on  which  a  spirit-level  may  be 
placed,  will  answer  for  levelling  the  foundation. 

After  the  foundation  is  level,  the  bed-plate  may  be  placed  on  it, 
either  by  means  of  a  crane,  block  and  tackle,  or  skids  and  block-  1 
ing,  after  which  it  may  be  tied  down  and  accurately  levelled.  It  ■ 
is  customary,  in  the  case  of  large  engines,  to  place  wedges  between  | 
the  bed-plate  and  foundation,  for  the  purpose  of  leaving  an  inter-  t 
stice  between  the  bottom  flange  of  the  bed-plate  and  the  brick  ^ 
work,  into  which  melted  sulphur  is  poured.    As  sulphur  is  less 


THE   engineer's    H  A  N  I)  Y -IU)0  K  . 


Influenced  by  a  change  of  temperature  than  any  other  known 
mineral,  it  is  of  great  value  as  a  bedding  for  heavy  steam-engines, 
and  other  machinery;  besides,  when  melted,  it  enters  every 
crevice,  and  as  soon  as  it  is  set  becomes  a  permanent  fixture.  To 
use  it,  it  is  necessary  to  seal  the  opening  between  the  bed-plate  and 
brick  work,  inside  and  out,  with  potter's  clay,  occasionally  leaving 
a  gate  or    sprue  "  through  which  the  molten  sulphur  is  poured. 

A  line  should  next  be  accurately  drawn  through  the  centre  of 
the  cylinder,  and  attached  to  some  permanent  object  at  the  back 
end  of  the  bed-plate;  another  line  should  be  drawn  at  right  angles 
to  this  through  the  centre  of  the  main  bearing ;  this  latter  will 
give  the  exact  location  of  the  off  pillow-block,  as  the  crank-shaft 
must  be  exactly  at  right  angles  with  the  horizontal  line  passing 
through  the  centre  of  the  cylinder.  The  fly-wheel  may  next  be 
swung  into  the  pit,  and  the  shaft  slipped  through  it  and  firmly 
keyed  at  the  right  position,  after  which  the  pillow-block  caps 
may  be  screwed  down,  the  front  head  of  the  cylinder  put  on,  the 
cross-head  placed  in  position,  the  piston  slipped  in,  and  the  con- 
nection between  the  cross-head  and  crank-pin  made  up.  Other 
numerous  details  might  be  mentioned,  but  they  never  all  apply  to 
any  individual  case,  and  when  any  of  them  present  themselves  as 
the  work  proceeds,  the  remedy  in  this  case  must  be  prescribed  by 
the  erecting  engineer.  In  setting  up  engines,  like  setting  valves, 
only  general  instructions  can  be  given,  and  it  is  impossible  to  lay 
down  any  that  would  apply  to  each  and  every  case. 

How  to  Reverse  an  Engine. 

Place  the  crank  on  the  dead-centre  and  remove  the  bonnet  of 
the  steam-chest ;  observe  the  amount  of  lead  or  opening  that  the 
valve  has  on  the  steam  end ;  then  loosen  the  eccentric  and  turn  it 
round  on  the  main  shaft  in  the  direction  in  which  it  is  intended 
the  engine  should  run,  until  the  valve  has  the  same  amount  of 
lead  on  the  other  end.  To  determine  whether  the  lead  is  exactly 
the  same  at  both  ends,  a  small  piece  of  pine  wood  may  be  tapered 
13  K 


146 


THE   engineer's  HANDY-BOOK. 


in  the  shape  of  a  wedge,  and  inserted  in  the  port ;  the  marks  left 
on  it  by  the  edge  of  the  port  and  the  lip  of  the  valve  will  show 
how  far  it  has  entered.  The  engine  should  then  be  turned  on  the 
other  centre  for  the  purpose  of  equalizing  the  lead ;  the  crank 
should  also  be  placed  at  half-stroke,  top  and  bottom,  for  the  pur- 
pose of  determining  whether  the  port  opening  is  the  same  in  both 
positions.  When  the  crank  is  at  half-stroke,  the  centre  of  the 
crank-pin  is  plumb  with  the  centre  of  the  crank-shaft. 

How  to  Repair  Steam-Engines. 

It  would  be  reasonable  to  suppose  that  any  machinist  would 
be  capable  of  repairing  steam-engines;  and  yet,  on  an  examination 
of  numerous  cases  w^here  repairs  have  been  done  by  persons  calling 
themselves  mechanics,  it  appears  that  very  few  machinists  are  fit 
to  be  trusted  to  do  so.  A  man  to  be  competent  to  do  repairs  must 
first  understand  the  original  character  of  the  engine  or  machine, 
and  its  defects,  whether  arising  from  design,  inferior  material,  or 
workmanship,  how  an  improvement  can  be  made  in  its  working, 
as  well  as  what  would  be  actually  an  improvement,  before  pro- 
ceeding to  make  it. 

The  first  step  in  repairing  an  engine  is  to  take  off  the  connect- 
ing-rod, cross-head,  both  cylinder-heads,  and  remove  the  piston ; 
then  pass  a  line  exactly  through  the  centre  of  the  cylinder,  and 
attach  it  to  some  fixed  object  at  the  back  end,  to  determine  if  the 
centre  of  the  crank-pin  is  in  line  with  the  centre  of  the  cylinder. 
If  not,  one  of  them  must  be  moved,  and  whichever  it  is  will  de- 
pend or^  the  diflficulty  to  be  encountered,  and  must  be  determined 
by  the  judgment  of  the  party  who  undertakes  the  repairs.  The 
cylinder  must  next  be  accurately  measured  at  both  ends  and  the 
centre,  for  the  purpose  of  determining  if  it  is  worn  larger  in  the 
centre  than  at  either  end,  or  worn  oval,  as  is  often  the  case. 

In  either  case  it  will  be  necessary  to  rebore  the  cylinder  and 
make  it  uniform  all  through.  It  is  next  necessary  to  caliper  thej 
cross-head,  wrist-  and  crank-pin,  to  see  if  they  are  worn  oval,  and! 


THE   engineer's  HANDY-BOOK. 


147 


if  80,  they  must  be  filed  round.  The  guides  should  then  be  tested 
with  an  accurate  parallel  piece,  to  ascertain  if  they  are  straight 
all  through ;  if  they  are  hollow  in  the  middle  or  at  either  end, 
they  must  be  taken  down  and  planed  straight.  If  the  piston-rod 
is  badly  fluted,  it  must  be  put  in  a  lathe,  returned,  and  filed ;  the 
rings  should  be  taken  off*,  placed  in  a  lathe-chuck,  and  faced  up 
on  both  ends,  and  if  they  are  cut  they  should  be  turned  true  and 
smooth.  The  cross-head  should  then  be  measured  crosswise  to 
determine  whether  the  guides  are  too  far  apart  or  not;  and  if  so, 
the  holes  in  the  studs  which  tie  them  to  the  bed-plate  must  be 
filed  oval  to  bring  them  to  a  proper  position.  If  the  valve  and 
seat  are  cut,  the  valve  must  be  taken  off*  and  planed  in  the  oppo- 
site direction  to  its  travel.  The  steam-chest  must  also  be  removed, 
and  the  valve-seat  straightened  by  filing  and  scraping,  after  which 
the  valve  may  be  carefully  fitted  to  it. 

The  flange  of  the  piston -head  and  follower-plate  should  be  faced 
up  in  a  lathe,  at  the  point  where  they  strike  the  rings,  and  the  lat- 
ter should  be  carefully  ground  and  scraped  on  to  them.  The  piston 
should  next  be  inserted  into  the  cylinder,  set  out,  and  the  cross- 
head  slipped  on,  connected  with  it,  and  levelled,  so  that  it  may 
stand  parallel  w^ith  the  centre  of  the  axis  of  the  cylinder  at  all 
points  of  the  stroke.  The  connecting-rod  boxes  should  be  ex- 
amined in  order  to  ascertain  if  they  are  "  brass  bound,"  and  if  so, 
they  should  be  filed  out.  The  main  pillow-block  bearing  should 
receive  attention,  in  order  to  determine  if  it  is  worn  oval  or  loose. 
In  fact,  every  part  should  receive  attention,  because  defects  that 
have  not  been  thought  of  may  be  revealed  as  the  work  progresses. 
It  has  been  generally  heretofore  supposed  that  any  one  bearing 
the  name  of  a  machinist  is  competent  to  repair  a  steam-engine, 
which,  of  course,  is  a  grave  error,  as  thousands  of  mechanics  fully 
competent  to  build  a  machine  are  totally  unfit  to  repair  it. 

This  arises  from  the  fact,  that  the  repairing  of  steam-engines 
and  other  machinery  requires  a  different  class  of  talent  from  that 
necessary  to  build  them.  A  machinist  may  be  a  good  hand  on 
either  a  vice,  lathe,  or  planer ;  he  may  be  a  thorough  fitter  and  a 


148 


THE   engineer's  HANDY-BOOK. 


neat  finisher,  and  yet  he  may  lack  that  keen  observation,  that  cool, 
patient,  and  searching  perseverance  which  are  so  essential  in  the 
party  that  will  become  an  adept  in  the  repairing  of  steam-engines 
and  other  machinery.  It  not  unfrequently  happens,  that  when 
everything  has  been  done  that  was  considered  absolutely  neces- 
sary, an  engine  works  badly  when  started  up,  which  is  very  dis- 
couraging to  any  one,  except  those  who  take  a  peculiar  interest  in 
ferreting  out  the  causes  of  minor  defects  which  have  been  over- 
looked when  the  more  prominent  ones  were  remedied.  Almost 
any  one  can  tell  if  an  engine  is  badly  out  of  line,  the  cylinder 
fluted,  or  the  crank-pins  loo^e  or  worn  oval ;  but  it  requires  a  dif- 
ferent kind  of  talent  to  determine  the  different  causes  for  the 
defective  working  of  steam-engines,  and  prescribe  a  remedy  for 
them,  as  many  of  them  apparently  did  not  exist  at  the  commence- 
ment of  the  work,  but  cropped  out  as  it  progressed.  One  of  the 
greatest  mistakes  in  the  repairs  of  steam-engines  and  other  ma- 
chinery, is  that  those  who  have  them  in  charge  are  expected  to  per- 
form the  work  in  too  limited  a  time.  This  being  impossible,  the 
only  resource  left  is  to  slight  it. 

How  to  Increase  the  Power  of  the  Steam-Engine. 

It  frequently  happens  that  engines  which  were  originally  of 
sufficient  power  to  do  the  work  of  a  manufacturing  establishment, 
become  unable  to  do  the  work,  owing  to  an  increase  in  the  busi- 
ness ;  and  while  the  cost  of  replacing  an  engine  with  one  of  sufl5- 
cient  power  would  be  a  matter  of  nominal  consideration,  the  time 
expended  in  removing  and  replacing  it  with  a  larger  one  might 
involve  a, serious  loss  to  the  owner,  in  case  he  had  large  orders  for 
goods  to  fill  at  profitable  prices.  Under  such  circumstances,  the 
three  most  practicable  ways  to  remedy  the  difficulty  for  the  time 
being  would  be — jirsty  to  raise  the  pressure,  providing  the  boiler 
is  considered  safe;  second,  to  increase  the  speed  of  the  engine; 
third,  to  replace  the  old  cylinder  with  a  new  one  about  two  inches 
larger  in  diameter,  which  would  of  course  involve  the  necessity  of 
a  new  piston,  steam-chest,  and  valve. 


THE   ENGINEER'S  HANDY-BOOK. 


149 


For  a  moderate  increase  in  power,  the  last  plan  would  be  the 
most  safe  and  practicable,  as  the  active  condition  of  steam-boilers 
is  not  always  understood,  and  without  a  thorough  knowledge  on 
the  subject  it  would  be  unwise  to  increase  the  pressure;  nor  should 
any  engine  be  run  at  a  higher  speed  than  it  is  capable  of  stand- 
ing without  springing  or  shaking  to  pieces.   The  increase  in  power 
that  would  result  from  replacing  the  old  cylinder  with  a  new  one 
two  inches  larger  in  diameter  may  be  illustrated  as  follows :  Take, 
for  instance,  a  10-inch  cylinder,  which  contains  78*54  square  inches 
in  area,  while  a  cylinder  12  inches  in  diameter  contains  113-09 
square  inches,  which  makes  a  difference  of  34*55  square  inches  in 
the  piston.    Now,  if  the  engine  having  a  lO-inch  cylinder  wa.%' 
unable  to  do  the  work  with  60  lbs.  pressure  per  square  inch,  it 
would  do  the  work  easily  with  the  12-inch  cylinder  at  the  same 
pressure,  as  the  new  cylinder  would  make  a  difference  of  from  5 
to  6  horse-power.    Measures  might  be  taken,  and  the  new  cylin. 
der,  piston,  and  steam-chest  prepared  and  placed  in  position  at  a 
given  time,  without  causing  any  interruption  to  the  business. 
Of  course  the  margin  for  increasing  the  size  of  cylinder  for  any 
!  engine,  and  using  all  the  other  original  parts  of  the  engine,  is  lim- 
ited, and  should  never  exceed  2  inches;  as,  to  exceed  that  limit,  the 
other  parts  would  be  too  light,  and  become  liable  to  spring.  To 
increase  the  speed  of  an  engine,  it  would  be  necessary  to  have  a 
new  counter-pulley,  so  that,  while  the  piston  velocity  is  increased, 
the  speed  of  the  shafting  may  remain  the  same.    An  engine  will 
j  develop  more  power  by  increasing  its  speed,  but  will  use  more 
I  steam,  and  as  a  consequence  more  fuel  will  be  consumed.  The 
overtaxing  of  steam-engines  and  boilers,  or  any  other  class  of 
j  machijies,  is  sure  to  induce  waste  either  in  fuel  or  wear  and  tear: 
I  but  there  are  circumstances  under  which  manufacturers  and  steam 
I  users  find  themselves  placed,  in  which  it  would  be  impossible  to 
1  avoid  waste.    Steam-engines  or  boilers,  or  any  other  class  of 
machines  that  is  too  large  or  too  small  for  the  work  to  be  per^ 
1  formed,  are  not  economical. 


13* 


150 


THE   ENGINEER'S  HANDY-BOOK. 


The  Improved  Greene  Automatic  Cut-Off  Engine. 

The  illustration  represents  the  Improved"  Greene  Automatic 
Cut-Off  Engine,  of  which  the  Providence  Steam-Engine  Company, 

Providence,  R.  I.,  are 
sole  builders. 

The  bed-plate  is  of 
the  girder  pattern,  sym- 
metrical in  appear- 
ance, and  of  ample 
strength.  The  slides 
are  cast  separate,  and 
secured  to  bed-plate  by 
dowels  and  bolts.  The 
main  journal-boxes  are 
made  in  four  pieces, 
and  provided  with  set- 
screw^s  and  check-nuts, 
which  permit  of  con- 
venient and  accurate 
adjustment.  The  gov- 
ernor is  of  the  Porter 
pattern,  and  is  driven 
by  a  flat  belt  from  the 
main  shaft.  The  valve- 
gear  is  detachable,  and 
is  so  controlled  by  the 
governor  that  the  cut- 
ting oflT  may  be  eflected 
from  zero  to  three- 
quarters  of  the  entire 
stroke.  The  valves  are 
four  in  number — two 
steam  and  two  exhaust 
— and  are  of  the  flat-slide  pattern.    The  power  which  moves  them 


THE   engineer's  HANDY-BOOK. 


151 


is  applied  parallel  to  and  in  line  with  their  seats,  so  that  they  can- 
not rock  or  twist — thus  obviating  the  tendency  to  wear  unevenly. 
The  steam-valves  when  tripped,  are  shut  by  the  combined  action 
of  a  weight  and  the  pressure  of  the  steam  on  the  large  valve-stems, 
thereby  insuring  a  quick  cut-off,  and  the  positive  closing  of  the  port, 
under  all  circumstances  of  speed  and  pressure.  The. steam-valves 
are  operated  by  toes,  on  the  inner  ends  of  two  rock-shafts  that 
connect  with  the  valve-stems  outside  the  steam-chest.  The  outer 
ends  of  the  rock-shafts  are  furnished  with  steel-tipped  toes. 

There  is  a  sliding-bar  carrying  tappets  which  receive  a  recipro- 
cating rectilinear  motion  from  an  eccentric  on  the  main  shaft. 
Below  the  sliding-bar  is  a  gauge-plate  connected  with  the  gov- 
ernor, which  receives  an  up  and  down  motion  from  a  reverse 
action  of  the  governor  balls. 

The  tappets  in  the  sliding-bar  are  supported  by  springs,  the 
lower  ends  of  which  rest  upon  the  gauge-plate ;  the  ends  of  the 
tappets  projecting  through  the  gauge-plate  with  nuts  upon  them 
secured  by  pins.  As  the  sliding-bar  moves,  one  of  the  tappets  is 
brought  in  contact  with  the  inner  face  of  the  toe  on  the  rock-lever, 
causing  it  to  turn  on  its  axis,  thereby  opening  the  steam-valve  at 
one  end  of  the  cylinder;  the  other  tappet,  meanwhile,  passes  under 
the  rock-lever, — without  moving  it, — the  toe  and  tappet  being  so 
bevelled  that  the  tappet  will  be  forced  down  against  the  action  of 
the  spring,  till  it  has  -passed  the  toe,  when  the  spring  causes  it  to 
resume  its  original  position,  prior  to  opening  the  steam-valve  at 
the  opposite  end  of  the  cylinder  upon  the  return  stroke  of  the  bar. 

As  a  result  of  this  motion,  the  tappet  always  gives  the  valves 
the  same  lead,  and  as  the  bar  moves  in  a  straight  line,  while  the 
I  toe  describes  the  arc  of  a  circle,  the  tappet  will  pass  by  and  liber- 
I  ate  the  toe,  which  is  brought  back  to  its  original  position  by  a 
I  w^eight,  and  the  steam  pressure  on  the  large  valve-stem,  which  thus 
I  closes  the  valve  and  cuts  off  the  steam.  The  liberation  of  the  toes 
I  will  take  place  sooner  or  later,  according  to  the  elevation  of  the 
I  tappet ;  that  is,  the  lower  the  tappets  are,  the  sooner  the  toes  will 
I  be  liberated,  and  vice  versa.    By  the  elevation  or  depression  of  the 


152 


THE   ENi^INEER's  HANDY-BOOK. 


gauge-plate,  the  period  of  closing  the  valves  is  changed,  while  the 
period  of  opening  them  remains  the  same.  The  adjustment  of  the 
gauge-plate  is  effected  directly  by  the  governor. 

Both  the  exhaust-valves  and  seats  are  convenient  of  access,  and 
removable  from  the  outside  of  cylinder.  These  valves  receive  their 
motion  from  a  separate  eccentric,  thus  allowing  of  easy  adjust- 
ment, without  interference  with  the  steam-valve  mechanism.  All 
the  connections  are  on  the  outside,  are  few  in  number,  and  have 
ample  bearing  surfaces,  insuring  freedom  from  rapid  wear  and  de- 
rangement. 

A  safety  stop-motion  is  combined  with  the  governor,  preventing 
the  admission  of  steam  should  the  governor-belt  run  off  or  break. 

The  cross-head  gibs  are  directly  opposite  the  centre  of  pin, 
thus  avoiding  any  cross  strain  upon  the  piston-rod ;  a  lack  of  at- 
tention to  this  point  has  been  the  cause  of^many  serious  accidents. 
The  steam-ports  are  large,  thus  insuring  the  full  pressure  of  steam 
to  the  point  of  cut-off.  A  very  desirable  feature  of  this  engine, 
and  one  that  will  be  appreciated,  is  the  method  of  connecting  the 
steam-valves  with  their  stems,  by  which,  if  water  should  accumu- 
late in  the  cylinder,  and  the  engine  be  started  without  the  usual 
precautions,  the  valves  wdll  lift,  giving  a  free  passage  of  the  water 
through  the  steam-ports.  The  engine  is  extremely  sensitive  to  the 
action  of  the  governor,  and  is,  therefore,  particularly  adapted  to 
those  situations  where  perfect  regulation  iS"  required.  All  parts 
are  well  proportioned,  made  of  best  material,  accurately  fitted,  and 
highly  finished. 

The  Dead-Centre. 

All  reciprocating  steam-engines  have  one  dead-centre  in  each 
stroke  and  two  in  each  revolution,  and  that  point  is  the  point  at 
which  the  steam  is  exhausted,  and  the  centre  of  the  crank-pin  is 
parallel  with  the  centre  of  the  axis  of  the  cylinder.  The  centre 
of  the  cross-head,  in  some  cases,  may  be  above  or  below  the  centre 
of  the  cylinder ;  but  by  placing  a  spirit-level  on  the  top  or  bottom 


THE   ENGINEER\s    HANDY -BOOK. 


153 


of  the  stub-end  strap,  the  dead-centre  may  be  easily  found.  The 
experienced  engineer  or  machinist  can  generally  tell  by  the  eye 
when  the  crank  is  at  the  dead-centre;  but  to  insure  accuracy  it 
is  always  better,  in  the  case  of  horizontal  engines,  to  try  it  with  a 
level,  and  in  vertical  engines  with  a  plumb-bob  and  line.  The 
cranks  of  all  engines  have  to  be  placed  accurately  on  the  centre 
when  the  valves  are  set. 

A  single  reciprocating  engine  is  completely  helpless  when  the 
crank  is  at  the  dead-centre,  and  would  stop  there  if  it  was  not  for 
the  momentum  of  the  balance-wheel.  Double  reciprocating  en- 
gines, such  as  locomotives  and  marine  engines,  which  have  their 
cranks  set  at  right  angles,  require  no  balance-wheel,  as  they  pull 
each  other  off  the  dead-centre,  in  consequence  of  one  crank  being 
at  its  full-power  point  while  the  other  is  at  the  weakest.  There 
are  some  engines,  such  as  the  rotary,  which  have  no  dead-centre 
in  their  revolution. 

The  Causes  of  Knocking  in  Steam-Engines. 

The  most  frequent  causes  of  knocking  in  steam-engines  are 

lost  motion  in  the  cross-head,  wrist-  and  crank-pin  boxes ;  loose- 
ness in  the  pillow-block  or  main-bearing  boxes ;  looseness  of  the 
piston-rod  or  folk  wer-plate ;  the  crank-pin  or  crank-shaft  being 
out  of  line  with  the  cylinder,  or  the  wrist-pin,  crank-pin,  or  main- 
bearing  journal  being  worn  oval;  the  slide-valve  having  too  much 
or  not  enough  lead  ;  the  exhaust  opening  being  too  soon  or  too  late; 
the  valve  being  badly  proportioned,  or  the  exhaust  passage  out- 
side of  the  cylinder  being  contracted. 

Other  causes  are  shoulders  being  worn  in  each  end  of  the 
cylinder,  in  consequence  of  the  packing-rings  not  travelling  over 
the  counter-bore  at  each  end  of  the  stroke ;  or  shoulders  being 
worn  on  the  guides,  resulting  from  the  cross-head  shoes  not  over- 
lapping them  when  the  crank  is  at  the  dead-centre ;  the  piston 
not  having  sufficient  clearance  at  either  end  of  the  cylinder,  in 
consequence  of  its  being  altered  by  taking  up  the  lost  motion  in 


154 


THE   ENGINEER'S   H  AND  Y-BOOK  . 


the  boxes ;  there  not  being  sufficient  draught  in  the  keys  to  take  up 
the  lost  motion  in  the  connecting-rod  boxes ;  the  packing  being 
screwed  too  tight  round  the  piston-rod;  excessive  cushioning,  re- 
sulting from  the  leaky  condition  of  the  piston,  which  allows  the 
steam  to  occupy  the  space  between  the  cylinder  and  piston-head, 
as  the  crank  approaches  the  centre,  thereby  subjecting  the  engine 
to  an  enormous  strain,  as  at  this  part  of  the  stroke  the  fly-wheel 
is  travelling  very  fast  and  the  crank  moving  very  slowly ;  or  lost 
motion  in  the  connection  by  which  the  slide-valve  is  attached  to 
the  rod.  Engines  out  of  line  frequently  knock  sideways  at  the 
half-stroke,  but  most  generally  at  the  outward  or  inward,  upper 
or  lower  dead-centre,  as  these  are  the  points  at  which  the  greatest 
strain  is  thrown  on  the  bearings,  in  consequence  of  the  direction 
of  the  connecting-rod  having  to  be  reversed.  The  foregoing  causes 
of  knocking  in  engines  constitute  the  principal  ones. 

The  knocks  arising  from  lost  motion  in  any  of  the  revolving, 
reciprocating,  or  vibrating  parts  of  an  engine  may  be  located  hj 
placing  the  finger  on  the  part,  while  the  cross-head  is  being  re- 
moved back  and  forth  on  the  guides  by  the  starting-bar;  but 
knocks  induced  by  the  valve  opening  or  closing  too  soon,  by  a 
contraction  of  the  exhaust,  or  by  the  valve  or  valves  being  im- 
properly set,  are  the  most  difficult  to  discover,  as  they  are  different 
from  those  induced  by  lost  motion,  the  sound  being  a  dull,  heavy 
thud,  in  many  instances  causing  the  engine,  building,  and  even  the 
foundation  to  vibrate  at  every  stroke.  While  an  intelligent  and 
careful  search  will  in  most  cases  result  in  successfully  locating  the 
knock,  some  will  for  a  time  baffle  the  most  expert  engineer.  In- 
stances are  not  uncommon  in  which  weeks  have  been  devoted,  en- 
gines taken  apart  and  put  together  again,  to  find  a  knock,  which, 
when  finally  discovered,  perhaps  turned  out  to  be  caused  by  a 
loose  crank-pin,  follower-plate,  or  key  in  a  fly-wheel.  It  not  un- 
frequently  happens  that,  after  every  other  means  have  been  re- 
sorted to,  the  indicator  has  to  be  applied,  in  order  to  determine 
the  precise  location  of  the  knock  or  "  thud." 

From  whatever  causes  knocking  in  engines  may  arise,  they  are 


THE   ENGINEER'S  HANDY-BOOK. 


155 


a  nuisance,  which  sounds  harshly  not  only  to  the  engineer,  but  to 
all  who  have  an  ear  for  natural  mechanics.  Nothing,  perhaps, 
makes  the  intelligent  engineer  feel  so  cheap  as  to  be  found  in 
charge  of  an  engine  that  knocks,  as  lookers-on  are  not  always 
capable  of  deciding  who  is  at  fault  —  the  engine  or  the  engineer. 

The  Remedies  for  Knocking  in  Steam-Engines. 

While  it  may  be  possible  in  most  cases  to  locate  the  knocking 

in  steam-engines,  and  explain  the  causes  from  which  they  arise,  it 
is  hardly  possible  to  prescribe  a  remedy  for  all,  as,  in  many  in- 
stances, it  must  arise  out  of  and  be  determined  by  the  circum- 
stances of  the  individual  case.  The  most  practical  method  of 
remedying  the  knocking  induced  by  the  crank-pin  being  out  of 
line,  is  to  place  the  crank-shaft  at  right  angles  with  the  centre  of 
the  cylinder,  remove  the  old  crank-pin,  rebore  the  hole  so  as  to 
bring  the  centre  of  the  new  pin  perfectly  in  line  with  the  axis  of 
the  cylinder,  and  replace  the  old  pin  with  a  new  one.  The  knock- 
ing induced  by  the  wrist-pin  and  crank-pin  becoming  worn  oval, 
may  be  remedied  by  filing  them  perfectly  round  ;  but  the  knock- 
ing caused  by  the  crank-shaft  journal  being  worn  out  of  round  is 
very  difficult  to  remedy;  in  fact,  there  is  hardly  any  remedy  for 
it,  except  to  remove  the  shaft,  true  it  up  in  a  lathe,  and  refit  the 
boxes,  which  operation  is  attended  with  a  good  deal  of  difficulty, 
more  especially  when  the  engine  is  large. 

Knocking  in  the  boxes  on  the  crank-pin  and  cross-head,  or 
valve-rod,  may  be  remedied  by  filing  out  the  boxes  and  readjust- 
ing the  keys,  or  by  putting  a  liner  behind  or  in  front  of  the  boxes, 
when  there  is  not  sufficient  draught  in  the  keys  and  gibs.  Knock- 
ing in  the  steam-chest  caused  by  looseness  in  the  valve  connec- 
tions may  be  remedied  by  readjusting  the  jam-nuts  or  the  yoke. 
Knocking  arising  from  this  cause  manifests  itself  more  frequently 
when  steam  is  shut  off*  from  the  cylinder,  preparatory  to  stopping 
the  engine,  than  when  the  engine  is  running ;  the  lost  motion  is 
taken  up  in  the  valve  connections  by  the  pressure  of  the  steam 
on  the  back  of  the  valve. 


156 


THE   engineer's  HANDY-BOOK. 


Knocking  in  the  piston  is  generally  caused  by  the  rod  becoming 
loose  in  the  head,  and,  if  it  continues  for  any  length  of  time,  it 
destroys  the  fit  of  the  rod  in  the  hole.  The  only  practical  remedy 
under  such  circumstances  is  to  remove  the  rod,  rebore  the  hole, 
and  bush  it  or  thicken  the  rod  at  that  point  by  welding,  and  fit  it 
to  the  head  after  the  hole  is  rebored  perfectly  true.  Knocking  in 
the  follower-plate  is  generally  caused  by  the  bolts  being  too  long, 
or  from  dirt  being  allowed  to  accumulate  in  the  holes,  which  pre- 
vents them  from  entering  sufficiently  far  to  take  up  the  lost  mo- 
tion in  the  plate,  and  may  be  remedied  by  shortening  the  follower- 
bolts,  or  removing  the  deposits  from  the  bottoms  of  the  holes,  as 
the  case  may  be. 

The  knocking  caused  by  shoulders  becoming  worn  in  the  cyl- 
inder at  each  end  can  be  remedied  by  reboring  the  cylinder,  and 
making  the  counter-bore  suflSciently  deep  that  a  part  of  one  of 
the  rings  will  overlap  it  at  each  end  of  the  stroke.  Knocking 
caused  by  shoulders  becoming  worn  on  the  guides  can  be  remedied 
by  planing  the  guides  and  making  the  gibs  or  shoes  suflSciently 
long  that  they  will  overrun  the  guides  when  the  crank  is  at  either 
centre.  The  knocking  induced  by  any  of  the  foregoing  causes  is 
generally  a  source  of  great  annoyance  to  the  engineer,  as  any  at- 
tempt to  adjust  the  boxes  on  the  cross-head  or  crank-pin,  or  the 
piston-packing  in  the  cylinder,  generally  aggravates  the  cause  of 
the  knocking,  as  any  adjustment  of  the  connecting-rod  boxes  alters 
the  position  of  the  piston  in  the  cylinder  and  the  cross-head  on 
the  guides,  and  causes  them  to  strike  harder  against  the  shoulders. 

Knocking  caused  by  the  valve  or  valves  being  improperly  set 
may  be  rem-edied  by  removing  the  bonnet  of  the  steam-chest  and 
adjusting  the  valve,  so  that  it  may  move  uniformly  on  its  seat, 
thereby  giving  the  same  amount  of  lead  at  each  end  of  the  stroke  ; 
then,  if  the  valve  is  well  proportioned,  and  the  connections  thor- 
oughly fitted  and  skilfully  adjusted  there  is  no  reason  why  the 
engine  should  knock  from  this  cause.  But  the  knocks  arising 
from  bad  proportion  in  the  valve  or  steam  passages  are  the  most 
difl[icult  of  all  to  remedy,  as  they  are  inherent  in  the  machine. 


THE   ENGINEER\s  HANDY-BOOK. 


159 


The  Douglas  Automatic  ('ut-Off  Engine. 

The  cuts  on  pages  157,  158,  represent  the  Douglas  Automatic 
Cut-OfT  Engine.  It  will  be  noticed  that  the  bed-plate  is  of  the 
girder-frame  pattern,  which  is  faced  up  to  receive  the  cylinder  at 
one  end  and  the  main  pillow-block  bearing  at  the  other.  The 
cylinder  rests  on  a  tapering  pedestal,  while  the  back  end  of  the 
bed-plate  and  crank-shaft  bearing  is  supported  by  a  double  leg, 
which  is  cast  solid  with  the  bed-plate.  The  pillow-blocks  at  the  cyl- 
inder-base are  placed  on  the  under  side,  and  are  situated  at  equal 
distances  from  the  centre,  which  facilitates  the  setting  up  of  the 
engine  or  placing  it  in  line,  as  all  that  is  necessary  is  to  level 
the  foundation  stone  and  place  the  engine  on  it.  The  cross-head 
guides  are  bored  out  cylindrical,  and  on  line  with  the  centre  of 
the  cylinder,  which  obviates  the  liability  of  the  engine  getting 
out  of  line. 

The  main  steam-valve  serves  both  for  induction  and  exhaust. 
The  exhaust  passes  through  its  centre  to  the  exhaust-port  at  the 
centre  of  the  cylinder.  It  receives  its  motion  from  an  eccentric, 
through  the  intervention  of  a  rocker-arm  and  small  take-up  connec- 
tions from  the  rocker-arm  to  the  valve-rod.  The  two  cut-off  valves 
are  flat,  and  slide  on  the  top  of  the  main  valve.  They  receive 
their  motion  from  an  extra  eccentric  and  rocker-arm.  On  this 
rocker-arm  is  a  disc,  pivoted  on  its  centre.  At  equal  distances 
from  the  pivot-pin,  in  opposite  directions,  are  tw^o  wrist-pins,  to 
which  the  cut-off  valve  on  the  frame  end  is  attached  by  a  take-up 
connection  and  spade-handle  joints  to  the  lower  pin  of  the  disc, 
while  the  steel  rod  passing  through  the  sleeve  to  move  the  other 
cut-off  valve  is  attached  to  the  other  pin  on  the  disc.  The  lever 
and  connection  attachments  from  the  governor  to  the  rocker  and 
disc  rotate  either  way,  separating  the  cut-off  valves  or  drawing 
them  nearer  together,  cutting  off  the  steam  earlier  or  later  in  the 
stroke,  to  accommodate  a  varying  load  and  pressure. 

The  governor  is  very  powerful,  sensitive,  and  positive  in  its  ac- 
tion, and  can  be  driven  by  either  belt  or  gearing.    Should  the  belt 


160 


THE   ENGINEER'S  HANDY-BOOK. 


shrink  or  slip  off,  the  engine  would  continue  to  run  the  same  as  be- 
fore it  broke,  as  there  would  be  no  power  to  change  the  valves,  since 
the  centrifugal  force  has  only  the  clutch-back  and  the  centre-weight 
to  lift.  The  driving  power  of  the  governor,  when  the  clutches 
are  in  contact,  acting  on  a  clutch  attached  directly  to  the  top  of 
the  screw,  turns  it  up,  and,  acting  on  a  clutch  attached  to  the  re- 
versed gear,  turns  it  down.  It  turns  the  screw  up  or  down  out 
of  clutch  before  the  governor  can  make  a  revolution. 

The  pillow-block  boxes  are  lined  with  Babbit  metal,  and  are 
provided  with  wedge-  and  draw-screws  for  the  purpose  of  taking 
up  the  wear  and  lost  motion.  The  wrist-  and  crank-pins,  valve- 
and  piston-rods,  are  made  of  steel  well  proportioned  and  well  fitted. 
The  fly-wheels  are  turned  off  on  the  face  and  sides  and  are  accu- 
rately balanced.  The  Douglas  engines  are  in  very  general  use  in 
the  Western  States  and  Territories,  and  wherever  used  their  repu- 
tation for  efliciency,  durability,  and  economy  has  added  to  their 
credit. 

Technical  Terms  Applied  to  Different  Parts  of 
Steam-Engines. 

Bonnet.  —  This  term  is  applied  to  the  covers  of  the  steam-chest 

Brasses.  — This  term  is  understood  to  apply  to  the  wrist-  and 
crank-pin,  or  connecting-rod  boxes ;  but  it  is  used  in  connection 
with  other  arrangements. 

Counterbore. — A  term  applied  to  recesses  in  the  ends  of  steam- 
cylinders  in  the  clearance  space,  over  which  the  piston-rings 
partly  travel.  The  object  of  the  counterbore  is  to  prevent 
shoulders  being  formed  at  each  epd  of  the  cylinder,  which  would 
induce  knocking  in  the  engine  when  any  changes  are  made  in 
the  connecting-rod  brasses. 

Jam-nuts.  — A  term  applied  to  the  nuts  which  lock  the  adjust- 
ing-screws in  the  piston-  and  valve-gear  of  steam-engines;  but 
jam-nuts  and  lock-nuts  are  used  for  many  other  purposes  in 
connection  with  the  steam-engine. 


THE   ENGINRER^S  HANDY-BOOK. 


161 


Pipe-swivel.  —  A  long  nut  containing  a  right-  and  left-hand 
thread.  It  is  used  for  adjusting  the  valve-gear  of  steam-engines, 
particularly  those  of  the  Corliss  type ;  but  the  pipe-swivel  is  used 
ior  many  other  purposes  than  this. 

Trunk. — A  term  applied  to  the  hollow  tube  connected  with 
the  pistons  of  trunk  engines  in  which  the  connecting-rod  oscil- 
lates. The  term  is  just  as  applicable  to  certain  other  parts  of 
machinery  and  arrangements  as  to  the  steam-engine. 

Trunnions.  —  A  term  applied  to  the  gudgeons  on  which  the 
cylinders  of  oscillating  engines  vibrate ;  but  it  may  be,  and  often 
is,  applied  to  other  machinery  as  well  as  oscillating  engines. 

Terras  Formerly  Applied  to  Dilferent  Parts  of  Steam- 
Engines,  but  whicli  have  become  Obsolete. 

Gab-lever. —  A  term  formerly  applied  to  an  arrangement  used 
for  lifting  and  lowering  the  eccentric-hook  oft*  and  on  the  rocker- 
pin. 

Pitman.  —  A  term  applied  to  the  crank-pins  of  steam-engines 
in  early  times. 

Plug -tree. — A  primitive  valve -gear  which  superseded  the 
scoggin. 

Radius-bar. — A  term  applied  to  the  connecting-rods  of  engines 
in  the  early  days  of  steam  engineering. 

Scoggin.  — This  name  w^as  given  by  the  boy  Potter  to  the  ar- 
rangement he  invented  for  opening  and  closing  the  valves  of 
steam-engines. 

j.  Shackle-bar. — This  term  was  used  to  denote  the  connecting- 
rod  of  steam-engines  at  a  period  when  they  were  generally  made 
of  wood,  and  strapped  with  iron  at  both  ends. 


Spider. — The  primitive  name  for  piston-heads  of  steam-enginee. 
U*  L 


162 


THE   ENGINEER'S  HANDY-BOOK. 


Questions : 

THE  ANSWERS  TO  WHICH  WILL  BE  FOUND  IN  THE  TEXT. 

Into  what  two  classes  are  steam-engines  divided,  regardless  of 
design,  general  arrangement,  etc.  ? 

Into  what  two  classes  are  steam-engines  in  general  sub-divided? 

Explain  the  difference  between  condensing  and  non-condensing 
engines,  their  advantages  and  disadvantages,  and  their  difference 
in  useful  results. 

What  are  the  advantages  of  compound  over  simple  engines,  and 

vice  versa  f 

State  the  formulae  for 'estimating  the  power  of  each  class  of 
engines. 

Explain  the  difference  between  automatic  cut-off  and  throt- 
tling engines,  and  the  advantages  of  the  one  over  the  other. 

Explain  the  advantages  and  disadvantages  of  the  various  cut- 
offs employed  on  stationary,  marine,  and  locomotive  engines.  > 

What  are  the  most  valuable  features  in  any  steam-engine? 

What  advantages  are  derived  from  duplicating  the  parts  of' 

steam-engines  ? 

How  would  you  proceed  to  fit  the  crank  of  a  steam-engine  on 

its  shaft  ? 

How  would  you  proceed  to  set  up  a  stationary  engine? 

How  would  you  proceed  to  repair  a  steam-engine? 

What  is  the  meaning  of  the  term  "  dead-centre  "  ?  How  would 
you  proceed  to  find  it  ? 

Explain  the  general  causes  of  knocking  in  steam-engines,  and 
the  remedies  for  the  same. 


THE   engineer's  HANDY-BOOK. 


163 


PART  THIRD. 


Bed-Plates  and  Housings. 

The  bed -plate  is  that  part  of  a  steam-engine  which  forms  the 
connection  between  the  cylinder  and  the  main  pillow-block  or 
crank-shaft,  and,  in  many  instances,  constitutes  the  support  on 
which  they  rest.  They  embrace  a  great  variety  of  shapes  and 
forms,  such  as  the  box  side  bed-plate,  girder-frame,  etc.,  which 
were  all  doubtless  designed  to  meet  some  peculiar  requirement, 
and  for  each  of  which  special  advantages  are  claimed,  the  girder- 
frame  being  in  most  favor  with  modern  engineers.  This  is  in 
part  due  to  the  fact,  that  the  necessary  rigidity  can  be  obtained 
with  less  metal  than  in  any  other  form,  and  that  the  strength  can 
be  more  equally  distributed  in  the  line  of  the  strain,  and  above 
and  below  it.  Bed-plates  are  subjected  to  transverse  in  addition 
to  tensile  and  compression  strains. 

In  designing  a  girder-frame,  if  it  is  to  be  supported  only 
at  the  ends,  due  allowance  must  be  made  for  transverse  strains 
due  to  the  thrust  of  the  connecting-rod.  The  amount  of  this 
strain  may  be  found  by  dividing  the  greatest  pressure  to  which 
the  piston  may  be  subjected  at  mid-stroke  by  the  quotient  ob- 
tained by  dividing  the  connecting-rod  by  the  crank.  Thus,  sup- 
pose the  area  of  the  piston  is  200  sq.  inches,  and  it  is  desired  to 
give  ample  strength  for,  say  80  lbs.  of  steam  at  mid-stroke; 
200  X  80  =  16,000  lbs.,  the  force  on  the  piston.  Then  suppose 
the  quotient  obtained  by  dividing  the  connecting-rod  by  the  crank 
is  5  ;  16,000  -i-  5  =  3200  lbs.,  the  pressure  on  the  slides  at  mid- 
stroke.  When  the  engine  runs  over,  that  is,  when  the  top  of  the 
fly-wheel  runs  from  the  cylinder,  the  weight  of  the  cross-head, 
and  half  the  weight  of  the  connecting-  and  piston-rods,  must  be 
added  to  this,  and  deducted  when  the  motion  is  in  the  opposite 
direction. 


164         THE  engineer's  handy-book. 

When  an  engine  runs  under,  a  support  under  the  frame  at  the 
6lides  (supposing  the  frame  to  be  of  the  girder  type)  would  not 
compensate  for  weakness  of  the  frame,  as  the  thrust  of  the  con-  ^ 
necting-rod  being  upwards,  the  upper  slide  would  give,  however 
securely  the  lower  one  might  be  supported.  The  term  housing  is 
applied  to  the  upright  frames  of  both  land  and  marine  engines. 

The  Housing.— This  term  is  applied  to  the  upright  frame  of 
vertical  engines  on  which  the  cylinder  rests,  and  which,  at  its  base, 
contains  the  main  pillow-block  bearings. 

Steam-Cylinders. 

The  cylinder  is  one  of  the  most  important  as  well  as  the  most 
expensive  parts  of  a  steam-engine ;  it  must  be  made  of  iron  pos- 
sessing the  qualities  of  hardness  and  toughness,  be  moulded  and 
cast  with  great  care,  and  bored  with  great  accuracy.  Cylinders, 
from  the  moment  they  are  put  into  use,  have  a  tendency  to  wear 
oblong,  also  to  wear  larger  in  some  places  than  others.  This  in- 
volves the  necessity  of  reboring  them,  which  is  one  of  the  largest 
Items  of  expense  incurred  in  the  repairs  of  a  steam-engine. 

There  are  certain  peculiarities  connected  with  the  wear  of 
steam-cylinders  upon  which  engineers  have  hitherto  been  unable 
to  agree,  among  which  is,  why  the  cylinders  of  different  engines 
of  the  same  size,  design,  and  manufacture,  and  under  the  same 
conditions,  wear  in  opposite  directions.  The  cylinders  of  some 
horizontal  engines  wear  more  on  the  lower  than  on  the  upper  side, 
while  others  of  the  same  size  and  build  wear  more  on  the  sides 
opposite  the  ports,  and  others  on  the  sides  next  the  ports.  Nor  is 
it  always  the  largest  cylinders  and  heaviest  pistons  that  wear  most 
on  the  lower  side  of  the  cylinder.  The  same  peculiarities  hold 
good  in  relation  to  vertical  engines.  On  some  lines  of  ocean 
steamers,  where  four  or  five  of  the  engines  were  built  by  the  same 
manufacturing  firm,  and  whose  design,  quality  of  material,  char- 
acter of  workmanship  were  intended  to  be  as  much  alike  in  every 
respect  as  it  was  possible  to  make  them,  it  was  found  on  exami- 


THE   engineer's  HANDY-BOOK. 


165 


nation  that  the  cylinders  of  all  were  worn  oblong  —  some  in  the 
middle,  others  at  both  ends,  and  others  still  at  only  one  end.  It 
is  a  general  impression  among  engineers,  that  the  cylinders  of  very 
large  horizontal  engines  are  more  liable  to  wear  oblong  than  those 
of  vertical  engines  of  the  same  bore ;  but  experience  and  obser- 
vation have  proved  this  to  be  a  mistaken  idea.  A  distinguished 
American  mechanic,  who  has  had  more  experience  in  boring  out 
the  cylinders  of  large  stationary,  locomotive,  and  marine  engines, 
within  the  past  ten  years  than  any  other  party  on  this  continent, 
asserts  that  there  is  no  accounting  for  the  manner  in  which  steam- 
cylinders  wear,  and  that  in  numerous  instances  he  found  the  cyl- 
inders of  the  engines  of  ocean  steamers  worn  oblong,  the  wear 
being  as  often  on  the  sides  next  the  ports  as  on  those  opposite. 
He  also  observed  in  horizontal  engines,  with  cylinders  36  inches 
in  diameter,  that  the  wear  on  the  bottom  was  hardly  perceptible, 
while  it  was  sufficiently  apparent,  on  either  one  side  or  the  other, 
to  involve  the  necessity  of  reboring. 

This  is  a  subject  worthy  of  study  and  investigation,  as  on  it 
depends  a  good  deal  of  the  economy  of  the  steam-engine.  Most 
engineers  would  be  inclined  to  think  that  such  freaks  were  due  to 
a  want  of  perfect  alignment,  as,  with  the  piston,  cross-head,  crank- 
pin,  perfectly  true  with  the  centre-line  of  the  cylinder,  and  with 
each  other,  it  is  difficult  to  see  why  the  piston  should  press  in  any 
direction  except  that  caused  by  gravity  ;  but  most  experienced 
engineers  are  aware  that  engines  that  are  supposed  to  be  per- 
fectly in  line  are  not  actually  so,  and  a  very  little  inaccuracy  in 
the  alignment  of  the  slides,  or  in  the  cross-head  guides,  may  suf- 
fice to  press  the  piston  out  of  centre.  Even  this  may  be  aggravated 
I  by  any  unequal  thickness  of  packing  in  the  stuffing-box  around 
I  the  piston-rod. 

Rule  for  finding  the  proper  thickness  for  steam-cylinders. 

Divide  the  diameter  of  the  cylinder  plus  2  by  16,  and  deduct 
u  j^T^th  part  of  the  diameter  from  the  quotient ;  the  remainder 
will  be  the  proper  thickness. 

^Rule  for  finding  the  required  diameter  of  cylinder  for  an 


166  THE   ENGINEER'S  HANDY-BOOK. 

engine  of  any  given  horse-power,  the  travel  of  piston  and  avail- 
able pressure  being  given. 

Multiply  33,000  by  the  number  of  horse-power ;  multiply  the 
travel  of  piston  in  feet  per  minute  by  the  available  pressure  in 
the  cylinder.  Divide  the  first  product  by  the  second  ;  divide  this 
quotient  by  the  decimal  '7854.  The  square  root  of  the  last  quo- 
tient will  be  the  required  diameter  of  cylinder. 

Rule  for  finding  the  cubic  contents  of  a  steam-cylinder. 

Multiply  the  area  of  cylinder  in  inches  by  the  length  of  the 
stroke  in  inches,  and  divide  this  product  by  1728.  The  quotient 
will  be  the  number  of  cubic  feet. 


TABLE 

;  HOWING  THE  PROPER  THICKNESS  FOR  STEAM-CYLINDERS  FROM  6  TO  90 

INCHES. 


Diameter 
of 

Cylinder. 

Thick- 
ness. 

Diameter 
of 

Cylinder. 

Thick- 
ness. 

Diameter 
of 

Cylinder. 

Thick- 
ness. 

Diameter 
of 

Cylinder. 

Thick- 
ness. 

6  in. 

•440 

28  in. 

1-595 

50  in. 

2-750 

72  in. 

3-905 

8 

•545 

30 

1-700 

52 

2-855 

74 

4-010 

10 

•650 

32 

1-805 

54 

2-960 

76  " 

4-115 

12 

•755 

34 

1-910 

56  " 

3-065 

78 

4-220 

14 

•860 

36 

2-015 

58 

3-170 

80  " 

4-325 

16  " 

•965 

38  " 

2-120 

6a 

3-275 

82  " 

4-430 

18  " 

1-070 

40 

2-225 

62 

3-380 

81 

4-535 

20  " 

1-175 

42 

2-330 

64  " 

3-485 

86  " 

4-640 

22  " 

1-280 

44 

2-435 

66 

3-590 

88 

4-745 

24  " 

1-385 

46  " 

2-540 

68  " 

3-695 

90  " 

4-850 

26  " 

1-490 

48 

2-645 

70  " 

3-800 

Rule  for  finding  the  quantity  of  steam  any  engine  will  use  at 
each  stroke  of  the  piston. 

Multiply  six  times  the  area  of  the  cylinder  by  \  the  stroke,  and 
divide  by  1728 ;  the  quotient  is  the  cubic  contents  of  the  cylinder 
in  feet.    Divide  this  quotient  by  the  cut-off  ^,  |,  or  |,  as  the  cas 
may  be ;  the  result  will  be  the  quantity  of  steam  used  at  each 
stroke  of  the  piston. 

Cylinder-head  bolts.  — There  does  not  appear  to  be  any  un 


THE   engineer's  HANDY-BOOK. 


167 


versal  rule  among  steam-engine  builders  for  proportioning  the 
strength  of  cylinder-head  bolts.  In  most  of  the  prominent  loco- 
motive works  in  this  country,  eleven  ^  bolts  for  an  18-inch  cyl- 
inder are  used ;  which  practice  is  based  on  the  assumption  that 
150  lbs.  of  steam  pressure  per  square  inch  is  the  maximum  strain 
to  which  the  area  of  the  head  can  safely  be  subjected.  Taking 
5800  as  the  sectional  area  of  each  bolt,  and  dividing  by  the  total 
pressure  of  steam  per  square  inch  against  the  cylinder-head,  we 
get  the  area  of  all  the  bolts  required.  This  quotient,  if  divided 
by  the  area  of  one  bolt,  will  give  the  whole  number  of  bolts  neces- 
sary. 

Fig.  \,  Fig.  3.  Pig".  2. 


The  Babbit  &  Harris  Steam- Piston. 

Steam-Pistons. 

The  piston  is  one  of  the  most  important  adjuncts  of  the  steam- 
engine  ;  all  the  other  parts  are  subsidiary  to  it.  No  part  of  the 
steam-engine,  since  its  advent,  has  proved  a  greater  source  of  an- 
noyance to  the  engineer,  and  anxiety  and  waste  to  the  steam  user. 
It  is  well  known  that  only  about  10  per  cent,  of  the  energy  stored 
\ip  in  good  fuel  is  utilized  in  the  best  class  of  steam-engines ;  this 


168 


THE   ENGINEER'S  HANDY-BOOK. 


being  a  fact,  however  economically  steam  may  be  generated  in 
the  boiler ;  unless  the  piston  is  steam-tight  and  capable  of  resist- 
ing the  strains  to  which  it  is  subjected,  very  little  of  the  work  it 
should  perform  will  be  realized. 

There  are  strong  reasons  why  every  portion  of  an  engine  should 
be  made  as  light  as  is  consistent  with  strength ;  but  this  is  espe- 
cially the  case  in  the  piston,  from  the  rapidity  of  its  reciprocating 
motion  and  the  strains  induced  by  the  momentum  on  the  crank- 
pin  and  other  parts  of  the  mechanism  ;  consequently,  the  essential 
requirements  of  a  good  piston  are  strength,  lightness,  simplicity, 
durability,  and  convenient  arrangement  for  easy  and  accurate  ad- 
justment. Though  the  U.  S.  Patent-Office  is  literally  crowded  with 
arrangements  which  are  claimed  to  be  improvements  on  all  former 
devices,  it  is  asserted  by  intelligent  engineers  that  a  good  piston 
is  as  much  of  a  necessity  as  it  was  in  the  days  of  Watt.  Nor  has 
it  ever  been  definitely  settled  which  of  the  steam-pistons  now  in 
use  is  best  suited  to  all  classes  of  engines ;  nor  is  it  at  all  likely 
that  any  one  piston  will  ever  be  able  to  establish  its  superiority 
under  all  circumstances.  It  may  be  said  of  steam-pistons,  as  of 
steam-engine  governors,  while  they  behave  well  in  the  majority 
of  cases,  there  are  circumstances  under  which  the  very  best  of 
them  .utterly  fail  to  give  satisfaction. 

The  depth  of  the  piston-rings,  in  good  practice,  should  be  about 
J  the  diameter  of  the  cylinder,  and  the  thickness  of  the  follower- 
plate  the  same  as  that  of  the  cylinder ;  so  that  the  whole  thick- 
ness of  the  piston  will  be  ^  the  diameter  of  the  cylinder  plus  twice 
its  thickness,  as  obtained  by  the  foregoing  rule.  The  diameter  of 
the  piston-rod  should  be  from  -5-  to  ^  that  of  the  cylinder  for  high- 
pressure  engines,  and  ^  for  condensing  engines. 

The  cuts  on  page  167  show  the  Babbit  &  Harris  Piston,  which 
is  in  very  general  use,  and  is  said  to  be  very  serviceable.  No.  1 
represents  the  packing  in  its  place ;  No.  2  shows  the  junk-ring, 
with  two  sections  of  packing  out ;  No.  3,  the  said  two  sections. 

The  inner  ring  of  steam-piston  packings,  against  which  the 
springs  press,  is  termed  the  junk-ring.  j 


THE   ENGINEER'S  HANDY-HOOK. 


169 


Piston-llods. 

The  diameter  of  piston-rods  varies  with  different  builders,  the 
range  being  between  ^  and  j^q  the  diameter  of  the  cylinder,  ac- 
(;ording  to  their  length  and  probable  maximum  pressure.  The 
high-pressure  piston-rods  of  the  American  line  of  steamships  are 
about  4  the  diameter  of  the  cylinders,  and  the  low-pressure  about 
j\.  The  piston-rod  of  the  Corliss  Centennial  Engine  was  about 
I  the  diameter  of  the  cylinder.  A  rod  y"^  the  diameter  would  be 
yJ(j  the  area  of  piston ;  and  if  100  lbs.  of  steam  were  acting  on 
the  piston,  the  strain  would  be  10,000  lbs.  per  square-inch  section 
of  rod,  which  is  about  ^  the  breaking  strength  of  good  iron. 

But  the  strain  on  a  piston-rod  is  alternately  tensile  and  com- 
pressive. Such  a  siae  would  evidently  do  for  such  a  pressure, 
though  it  might  not  break  so  long  as  it  was  not  subjected  to  any 
undue  strains  from  accidental  causes,  such  as  water  in  the  cylinder, 
etc.  On  the  other  hand,  the  largest  size  in  use  —  I  the  diameter 
of  the  cylinder  —  would  be  the  area,  on  which  the  strain  due 
to  100  lbs.  of  steam  would  be  3600  lbs.  per  square-inch  section, 
which  is  fairly  within  the  limits  of  perfect  safety.  But  the 
pressure  on  the  piston  is  not  the  main  consideration  in  deter- 
mining the  size  of  the  rod,  as  accidental  strains,  to  which  it  is 
liable  to  be  subjected,  must  be  adequately  provided  for.  Some  of 
these  strains  bear  no  relation  to  the  steam  pressure,  so  that  the 
diameter  of  the  piston  should  be  made  the  main  factor  in  de- 
termining the  size  of  the  rod.  Bourne's  rule  is  to  multiply  the 
diameter  of  the  cylinder  in  inches  by  the  square  root  of  the 
pressure  on  the  piston  in  pounds  per  square  inch,  and  dinde 
the  product  by  50.    The  quotient  is  the  size  of  the  piston-rod. 

Piston-rods  may  be  smaller  in  diameter  than  the  foregoing,  if 
made  of  steel,  and  if  they  possess  sufficient  rigidity  and  strength 
to  resist  all  strains  to  which  they  may  be  exposed,  and  at  the  same 
time  induce  less  friction,  do  more  service,  with  less  liability  to  flute 
or  require  returning,  while  the  difference  in  first  cost  would  be 
!  very  trifling,  and  that  of  fitting  about  the  same. 
15 


170  THE  engineer's  HANBY-BOOK. 


TABLE 


OF  UNITS  OF  HORSE-POWER  FOR  DIFFERENT  PISTON  SPEEDS. 

The  following  table  will  supply  any  units  of  horse-power,  be- 
sides those  already  given,  for  any  other  velocity  of  piston  by  mul- 
tiplication or  division.  For  example,  a  piston  of  12  inches  diam- 
eter, at  400  feet  per  minute,  gives  1*366  horse-power  for  every 
pound  average  pressure  on  each  square  inch,  and  will  give  one-half 
or  double  this  amount  at  speeds  of  200  or  800  feet  a  minute. 


INDICATED    HORSE-POWER   FOR   EACH    POUND  AVERAGE  PRESSURE 
PER  SQUARE  INCH,  WITH  DIFFERENT  DIAMETERS  AND 
SPEEDS  OF  PISTON. 


SPEED  OF  PISTON  IN  FEET  PER  MINUTE. 


Diane 

0 

Cylii 

240 

300 

350 

400 

450 

500 

550 

600 

Inches. 

4 

*091 

•114 

-133 

-152 

•171 

*19 

•209 

•228 

A  1 

•115 

•144 

-168 

•192 

-216 

"24 

-264 

-288 

5 

•144 

•18 

-21 

-24 

-27 

-30 

-33 

-36 

5i 

'173 

-252 

-288 

•324 

ou 

-432 

6 

•205 

-256 

•299 

•342 

•385 

•428' 

:471 

•513 

•245 

-307 

•391 

•409 

•461 

•512 

-563 

-614 

7 

•279 

-348 

•408 

•466 

•524 

•583 

-641 

•699 

n 

•321 

-401 

•468 

-534 

•602 

•669 

•735 

-802 

8 

•365 

-456 

•532 

•608 

-685 

•761 

•837 

•912 

8i 

•413 

•516 

-602 

-688 

•774 

-86 

•946 

1-032 

9 

•462 

-577 

-674 

•770 

•866 

•963 

1-059 

1-154 

91 

•515 

-644 

-751 

•859 

•966 

1-074 

1-181 

1-288 

10 

•571 

-714 

•833 

-952 

1-071 

1-390 

1-309 

1-428 

101 

•63 

-787 

•919 

1-050 

1-181 

1-313 

1-444 

1-575 

11 

•691 

-864 

1-008 

1-152 

1-296 

1-44 

1-584 

1-728 

Hi 

•754 

•943 

M 

1-257 

1-414 

1-572 

1-729 

1-886 

12 

•820 

1-025 

1-195 

1-366 

1-540 

1-708 

1-880 

2-050 

13 

•964 

1-206 

1-407 

1-608 

1-809 

2*01 

2-211 

2-412 

14 

J^119 

1-398 

1-631 

1-864 

2-097 

2-331 

2-564 

2-797 

15 

1^285 

1-606 

1-873 

2-131 

2-409 

2-677 

2-945 

3-212 

16 

1^461 

1-827 

2-131 

2-436 

2-741 

3-045 

3-349 

3-654 

17 

1-643 

2-054 

2-396 

2-739 

3-081 

3-424 

3-766 

4-108 

18 

1-849 

2-312 

2-697 

3-083 

3-468 

3-854 

4-239 

4-624 

19 

2-061 

2-577 

3-006 

3-436 

3-865 

4-295 

4-724 

5-154 

2Q 

2-292 

2-855 

3-331 

3-807 

4-265 

4-759 

5-234 

5-731 

21 

2-518 

3-148 

3-672 

4-197 

4-722 

5-247 

5-771 

6-296 

22 

2-764 

3-455 

4-031 

4-607 

5-183 

5-759 

6-334 

6-911 

THE 


ENGINEER'S  HANDY-BOOK. 
TABLE  —  ( Continued.) 


171 


INDICATED    HORSE-POWER   FOR   EACH    POUND  AVERAGE  PRESSURE 
PER  SQUARE  INCH,  WITH  DIFFERENT  DIAMETERS  AND 
SPEEDS  OF  PISTON. 


neter 
of 

nder. 

SPEED  OF 

PISTON  IN  FEET  PER  MINUTE. 

•p  5 

240 

300 

350 

400 

450 

500 

550 

600 

Inches. 

23 

3-776 

4*405 

5*035 

5*664 

6*294 

6*923 

<  ooz 

24 

Q.rtQQ 

4*111 

4*797 

5*482 

6*167 

6*853 

7*538 

Q.OOQ 

0  zzo 

25 

6  oby 

4-461 

5*105 

5*948 

6*692 

7*436 

8*179 

26 

6  obi 

4*826 

5*630 

6*435 

7*239 

8*044 

8*848 

y  boz 

27 

A  •!  c:q 

4  loy 

5*199 

6-066 

6*932 

7-799 

8*666 

9*532 

1  A.QAQ 

lu  oyy 

28 

4  477 

5*596 

6-529 

7*462 

8-395 

9*328 

10*261 

11  lyo 

29 

4  oUo 

6*006 

7-007 

8*008 

9-009 

10*01 

11*011 

iz  yjiz 

30 

At 

O  141 

6*426 

7-497 

8*568 

9*639 

10*71 

11*781 

iZ  oOZ 

31 

0  4oo 

6 '865 

8-001 

9*144 

10*287 

11*43 

12*573 

16  i  lb 

32 

0  o4o 

7-308 

8-526 

9*744 

10*962 

12*18 

13*398 

1  A 'Al A 

14  bib 

33 

D  ZlO 

7-770 

9*065 

10*360 

11*655 

12*959 

14*245 

lo  o4 

34 

b  oy 

8-238 

9*611 

10*984 

12*357 

13*73 

15*103 

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35 

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8-742 

10*199 

11*656 

13*113 

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16*027 

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36 

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9-252 

10*794 

12*336 

13*878 

15-42 

16*962 

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37 

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9*774 

11*403 

13*032 

14*861 

16-29 

17*919 

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38 

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10*308 

12*026 

13*744 

15*462 

17-18 

18*898 

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10*86 

12*67 

14*48 

16*29 

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13*328 

15*232 

17*136 

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18*009 

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16*792 

18*901 

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18*424 

20*727 

23-03 

25*333 

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19*272 

21*681 

24-09 

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20*144 

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19*187 

21*928 

24*669 

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30*151 

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19-999 

22*856 

25*713 

28*57 

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23*8 

26*775 

29-75 

32*725 

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51 

14-832 

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24*76 

27*855 

30*95 

34*045 

37*08 

52 

15-437 

19-296 

22*512 

25*728 

28-944 

32*16 

35*376 

38*592 

53 

16-041 

20*052 

23*394 

26*736 

30-078 

33*42 

36*762 

40*104 

54 

16-656 

20*82 

24*29 

27*76 

31-23 

34*7 

38*17 

41*64 

55 

17-275 

21*594 

25*193 

28*792 

32*391 

35*99 

39*589 

43*188 

56 

17-909 

22*386 

26*117 

29*848 

33*579 

37*31 

41*041 

44*772 

57 

18-557 

23*196 

27*062 

30-928 

34*794 

38*66 

42*526 

46*392 

58 

19-214 

24*018 

28*021 

32*024 

36*027 

40*03 

44*033 

48  036 

59 

19-902 

24*852 

28*994 

33*136 

37*278 

41*42 

45*562 

49*704 

60 

20-558 

25*698 

29*981 

34*264 

38*547 

42*83 

47*113 

51*396 

72 


THE   engineer's  HANDY-BOOK. 


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THE   ENGINEER  S  HANDY-BOOK. 


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THE   engineer's  HANDY-BOOK. 


175 


1 


Of 


Piston,  Connecting-Rod,  and  Crank  Connections. 
An  idea  very  generally  prevails  among  engineers  that  the 
craDk  of  a  steam-engine  travels 
faster  at  one  part  of  the  stroke 
than  at  the  other.  This  is  evident- 
ly a  mistake.  The  crank  travels 
at  a  uniform  speed  throughout  its 
revolution,  but  the  piston  travels 
farther  to  make  one-half  its  stroke 
than  the  other>  If  the  connecting- 
rod  were  indefinitely  long,  or  a 
slotted  yoke  were  substituted  for  it, 
the  movement  of  the  piston  would 
be  determined  by  the  crank  alone; 
its  points  of  mid-travel  would  cor- 
respond exactly  with  the  corre- 
sponding points  in  the  travel  of  the 
crank,  and  the  piston  would  occupy 
the  same  position  at  the  first  and 
last  half  of  each  stroke.  But  in 
consequence  of  the  distorting  action 
of  the  connecting-rod,  the  piston 
travels  farther  during  the  half  of 
each  stroke  farthest  from  the  crank, 
and  consequently,  when  the  crank 
is  at  its  point  of  mid-travel,  that  is, 
when  it  is  perpendicular  to  the 
axial  line  of  the  cylinder,  the  piston 
is  nearer  the  crank  than  its  point 
of  mid-travel  by  an  amount  which 
varies  inversely  with  the  length  of 
the  connecting-rod,  and  which  is 
equal  to  the  difference  between  the 
base  and  the  hypothenuse  of  the 
right-angled  triangle  formed  by  the 


176 


THE   engineer's  HANDY-BOOK. 


connecting-rod,  crank,  and  the  included  portion  of  the  line.  Now 
the  square  of  the  hypothenuse  of  a  right-angled  triangle  is  equal 
to  the  sum  of  the  squares  of  the  other  two  sides. 

The  crank  of  a  steam-engine  moves  six  times  as  far  while  the 
piston  is  travelling  the  first  inch  of  the  stroke  as  while  it  is  mak- 
ing the  middle  inch ;  a  little  over  twice  as  far  while  the  piston  is 
moving  the  second  inch ;  a  trifle  over  1^  times  as  far  while  the 
piston  moves  the  third  inch ;  and  less  than  1^  times  as  far  while 
the  piston  is  making  the  fourth  inch.  The  crank  also  travels  less 
when  the  piston  is  making  the  last  inch  of  the  stroke  than  it  does 
while  it  is  making  the  first.  Another  fact,  not  generally  recog- 
nized by  inexperienced  persons,  is  that  the  crank  of  a  steam- 
engine  at  certain  points  travels  a  considerable  distance,  while  the 
cross-head  has  a  motion  which  is  hardly  perceptible. 

Rule  for  finding  the  distance  the  piston  is  ahead  of  a  central 
position  in  the  cylinder  on  the  forward  stroke,  and  also  the  dis- 
tance which  it  lags  behind  on  the  backward  stroke. 

Subtract  the  square  of  the  length  of  the  crank  from  the  square 
of  the  length  of  the  connecting-rod ;  find  the  square  root  of  the 
diflference  or  remainder,  and  subtract  it  from  the  length  of  the 
connecting-rod.  The  remainder  will  be  the  variation  of  the  piston 
from  a  central  position  when  the  crank  is  at  right  angles  to  th© 
centre  line  of  the  engine. 

Example.  —  Length  of  crank,  12  in. 
liongth  of  connecting-rod,  72  " 
Then  72^  =-5184  in. 
12'=  lU  " 

Diflference  ^  5040  " 

x/5040  =  70-992  in.;  and 
72 

70-992 

1-008,  which  is  the  variation  in 
inches. 


THE   engineer's  HANDY-BOOK. 


177 


The  Reynolds  Corliss  Engine. 

The  cuts  on  pages  178, 179,  represent  the  front  and  back  views 
of  the  Reynolds  Corliss  Engine.  It  will  be  observed  that  the 
frame  is  of  the  girder  pattern,  the  front  end  of  which  is  faced  up 
to  receive  the  cylinder  and  slides,  while  the  back  end  contains 
the  pillow-block  bearing;  the  whole  being  supported  by  three  pair 
of  legs,  which  insures  rigidity  and  prevents  the  possibility  of 
springing,  in  case  the  engine  should  be  run  at  a  high  rate  of 
speed  or  loaded  beyond  its  rated  capacity.  The  cross-head  has 
its  support  on  the  slides,  directly  opposite  the  centre  of  the  cross- 
head  pin,  thus  avoiding  the  springing  and  final  breaking  of  piston- 
rods,  as  is  often  the  case  where  the  support  is  carried  back  of  the 
centre  of  the  cross-head,  as  is  done'  in  most  engines  of  this  type. 
It  is  provided  with  convenient  mechanical  arrangements  for  easy 
and  accurate  adjustment  in  case  of  wear. 

The  valves  are  of  such  construction  that  they  have  double  the 
wearing  surface  ordinarily  found  in  engines  of  this  type.  This 
obviates  the  rapid  wear  of  the  seats,  which  must  occur  where  the 
wearing  surfaces  are  small ;  while,  in  consequence  of  the  peculiar 
construction  of  the  valve-gear  of  these  engines,  they  can  be  run 
at  any  desired  speed.  The  valves  open  with  perfect  regularity 
and  close  instantaneously,  which  is  a  feature  of  great  importance 
in  itself,  especially  in  flouring-mills,  as  it  admits  of  the  line-shafting 
being  coupled  directly  to  the  engine-shaft,  thus  avoiding  the  use 
of  expensive  counter-gearing,  and  still  giving  the  fly-wheel  sufli- 
cient  motion  to  properly  "  lead  "  the  stone  and  avoid  "  backlash.'' 
No  springs  are  required  on  either  steam-  or  exhaust-valves.  The 
steel  catches  used  for  opening  and  liberating  the  steam- valves  are 
so  constructed  and  arranged  as  to  give  eight  wearing  faces  on  each 
piece;  while  by  unhooking  the  eccentric-rod,  all  the  valves  can 
be  easily  moved  and  the  engine  worked  by  hand,  which  prevents 
the  liability  of  its  catching  on  the  centre,  which  is  a  source  of 
annoyance,  especially  in  the  case  of  large  engines.  The  liberating 
portion  of  the  valve-gear  is  claimed  to  be  an  improvement  on  any 

M 


180 


THE   ENGINEER'S  HANDY-BOOK. 


other  arrangement  employed  on  any  Corliss  engine  in  use  at  the 
present  day. 

Some  of  the  most  important  features  of  the  Reynolds  Corliss 
Engine  are  that  they  are  stronger  and  heavier  than  most  engines 
of  that  class ;  that  the  valves  are  under  the  complete  control  of 
the  governor,  which  is  very  powerful  and  sensitive,  thus  insuring 
uniformity  in  speed,  which  is  a  feature  of  great  importance  for 
milling  and  most  other  manufacturing  purposes ;  that  the  valve- 
gear  is  simple  and  conveniently  arranged  for  accurate  adjustment ; 
that  the  fly-wheel  is  turned  on  the  face  and  sides  and  accurately 
balanced ;  that  the  wearing  surfaces,  whether  revolving  or  rub- 
bing, are  ample,  which  prevents  the  possibility  of  rapid  wear  and 
the  expense  of  repairs ;  and  that  the  cross-head  pin,  crank-pin,  and 
piston-rod  are  made  of  steel,  and  the  crank-shafts  of  the  best  ham- 
mered iron. 

The  Reynolds  Corliss  engines  are  in  very  general  use,  and  have 
a  well-earned  reputation  for  durability,  efficiency,  and  economy. 
The  condenser  and  air-pump  are  new  in  design,  simple,  and  effi- 
cient ;  in  fact,  the  whole  design  and  arrangement  of  these  engines 
show  them  to  be  the  result  of  mature  mechanical  deliberation. 
They  are  manufactured,  both  condensing  and  non-condensing, 
simple  and  compound,  of  any  size  and  power,  to  meet  the  re- 
quirements of  purchasers,  by  Edward  P.  Allis  &  Co.,  Milwau- 
kee, Wis. 

Steam-  and  Exhaust-Pipes. 

The  diameter  of  the  steam-pipe  varies  with  leading  engine 
builders  between  i  and  |  the  diameter  of  the  cylinder,  the  exhaust- 
pipes  being  from  about  30  to  50  per  cent,  larger.  Some  builders 
make  them  little,  if  any,  larger;  but  too  small  steam-  and  exhaust- 
pipes  are  a  prevailing  vice  amongst  small  builders,  especially 
those  in  country  districts,  who  do  not  use  an  indicator  to  determine 
their  proportions.  The  proper  diameter  for  steam-  and  exhaust- 
pipes  may  be  found  by  multiplying  the  diameter  of  the  piston  in 
inches  by  its  speed  in  feet  per  minute,  and  dividing  the  product 


THE   engineer's  HANDY-BOOK. 


181 


by  1440  for  steam-  and  1140  for  exhaust-pipes  ;  the  quotient  will 
be  the  diameter  of  the  pipes  in  inches.  For  short  and  direct 
pipes,  however,  the  divisor  may  be  increased  to  2000  for  steara- 
and  1440  for  exhaust-pipes.  These  latter  divisors  will  give  pro- 
portions a  trifle  larger  than  the  average,  especially  for  exhaust. 

Rock-Shafts. 

Some  engine  builders  make  the  diameter  of  the  rock-shaft  ] 

the  diameter  of  the  crank-shaft;  if  subjected  to  torsion,  it  should 
be  i,  and  in  some  cases  ^  ,  the  diameter.  The  torsion  on  a  shaft  is 
in  proportion  to  the  length  of  the  arm  to  which  the  valve  is  at- 
tached. About  10  times  the  area  of  the  slide-valve  in  square 
inches  will  nearly  equal  the  force  in  pounds  required  to  move  it 
under  100  pounds  steam  pressure,  though,  when  dry  or  starting,  it 
may  amount  to  12  times  or  more.  The  diameter  of  a  rock-shaft 
may  be  found  by  the  following  rule.  Multiply  the  maximum  re- 
sistance in  pounds  by  the  length  of  the  arm  which  divides  the 
valve,  and  divide  the  product  by  128;  the  cube  root  of  the  quo- 
tient will  be  the  diameter  of  the  shaft  in  inches.  The  size  thus 
found  will  answer  for  ordinary  wrought-iron  shafts,  and  w^ill  resist 
greater  strain  than  the  above  rule  provides  for.  The  rocker  and 
rock-shaft  are  being  fast  superseded  by  the  guide-block. 

Cross-Head  Bearings. 

The  area  of  the  wearing  surface  of  a  cross-head  (that  is  to 
say,  ^  the  total,  above  and  below)  should  not  be  less  than  \  the 
area  of  the  piston,  nor  ever  exceed  i  of  it.    Many  steam-engine 
builders  make  the  length  of  the  cross-head  bearings  §  the  diameter 
of  the  cylinder,  and  their  width  ^\  of  the  same,  which  appears  to 
I  be  a  good  proportion,  and  may  be  ilhisirated  as  follows:  |  of  a 
;  12  in.  cylinder  is  8  inches  in  length,  and      is  2^  inches  in  width, 
which  gives  20  sq.  inches  for  each  shoe,  or  40  for  both,  which  is  a 
1  good  proportion  ;  but  it  should  be  slightly  greater  in  the  case  of 


182 


THE  engineer's  HANDY-BOOK. 


short  connected  engines  running  at  a  high  speed.  The  cross-head 
gibs  are  generally  termed  shoes,  and.  the  grooves  in  which  they 
move  are  called  Vs. 

Valve-Rods. 

The  diameter  of  valve-rods  varies  for  moderate  sized  engines 
from  to  the  diameter  of  the  cylinder.  Their  diameter  in 
any  case  should  be  proportioned  to  the  size  of  the  valve,  whether 
it  is  balanced  or  not.  If  the  area  of  the  valve  be  considered 
as  a  piston  of  such  area,  \  its  diameter  will  bear  about  the  same 
relation  to  its  maximum  strain  as  piston-rods  do ;  but  valve-rods 
are  generally  made  somewhat  larger  than  such  a  rule  would  give, 
because  they  are  not  so  well  protected  against  side  strains  as  pis- 
ton-rods. Probably,  since  the  area  of  a  piston-rod  should  be  from 
3^     Z(5        ^^^^  piston,  according  to  its  length  and  ma- 

terial (steel  may  be  smallest),  a  valve-rod  should  be  about  from 
siir     sItt  unbalanced  area  of  the  valve  for  high-pressure 

engines. 

The  Eccentric. 

The  eccentric. —  An  eccentric  is  substantially  a  crank,  with  its 
pin  enlarged  in  diameter  so  as  to  inclose  the  shaft  on  which  it  is 
placed  within  its  periphery.  It  gives  exactly  the  same  motion 
that  would  be  'obtained  from  an  ordinary  crank  of  equal  throw. 
The  eccentric  is  sometimes  called  a  cam,  which  is  erroneous,  as  the 
latter  is  always  used  to  obtain  a  motion  different  from  what  can 
be  obtained  from  a  crank.  The  term  "  cam/'  when  used  without 
qualification,  is  indefinite,  and  conveys  no  impression  of  its  precise 
form  or  functions.  It  is  a  mechanical  element  of  such  a  form 
that  a  solid  body  held  against,  but  not  revolving  with,  the  pe- 
riphery of  contact  may  have  an  intermittent,  alternating  motion. 

Fore  eccentric^  —  A  "  term  "  applied  to  the  eccentric,  which  is 
connected  by  its  rod  to  the  upper  part  of  the  link,  to  move  the! 
valve  for  the  forward  motion ;  but  the  reason  that  the  forward 
motion  is  derived  from  the  upper  end  of  the  link  arises  from 


THE   ENGINEER'S   HANDY-BOOK.  183 


conv^i.xie..ce,  and  not  from  necessity.  The  reverse  conditions  could 
be  introduced  very  easily. 

Back  eccentric.  —  The  eccentric  connected  to  the  lower  end  of 
the  link  by  which  the  valves  are  adjusted  for  the  backward  motion. 

Throw  of  the  eccentric. —  The  "term''  throw  of  the  eccentric 
is  understood  to  be  the  same  as  the  travel  it  imparts  to  the  valve, 
and  which  is  understood  to  be  equal  to  the  width  of  both  steam- 
ports  with  the  lap  added. 

Angular  advance  of  the  eccentric  means  the  angle  at  which  it 
stands  in  advance  of  that  which  it  would  occupy  if  the  valve 
were  in  the  centre  of  its  travel,  and  the  crank  at  its  centre. 


The  Crank. 


The  generally  prevaler^t  idea  among  mechanics  that  there  is  an 
actual  loss  of  power  in  the  use  of  the  crank,  has  stimulated  in- 
ventors to  substitute  for  it  a  device  that  would  utilize  all  the  power 
exerted  against  the  piston  900. 
without  loss.  As  a  result,  the 

U.  S.  Patent-Office,  as  well  as  C(^\ 
those  of  the  different  coun- 
tries of  Europe,  are  crowded 
with  arrangements  intended 
to  supersede  the  crank  ;  the 
most   popular,  and  conse-i8(K~'Nl";~' 
quently  the  most  frequently 
resorted  to,  being  the  rotary  \ 
engine,  in  which  the  effective 
force  of  the  steam  would  be 
constant,  while  in  the  case  of 
the  crank  it  is  intermittent ; 
but,  so  far,  no  rotary  arrangement  has  ever  been  able  to  compete, 
in  point  of  economy,  with  the  reciprocating  motion  of  the  crank. 

Strictly  speaking,  there  is  no  loss  of  power  in  the  use  of  the 
crank,  as,  while  there  is  a  great  variation  in  the  power  a  given 


^270° 


j_  360° 


184 


THE   ENGINEER'S  HANDY-BOOK. 


pressure  of  steam  can  exert  at  different  points  of  the  stroke,  it  is 
known  that  when  the  power  is  least  the  consumption  of  steam  is 
least.  Suppose  an  engine  has  2-feet  stroke,  the  piston  would  travel 
4  feet  for  each  revolution ;  during  each  stroke  the  effective  length 
of  the  crank  varies  from  0  to  1  foot ;  its  average  effective  length 
would  be  equal  to  the  radius  of  a  circle  whose  circumference  was 
4  feet,  or  7*68  inches.  The  power  of  the  engine  would  be  the 
same  as  if  it  acted  on  a  constant  crank  of  7*68  inches,  and  the 
displacement,  and  consequently  the  consumption  of  steam,  would 
be  the  same  as  before. 

If  the  piston  acted  on  a  constant  or  average  crank  of  12  inches 
in  length,  it  must  travel  a  distance  equal  to  the  circumference  of 
a  24-inch  circle,  or  63|  inches.  Though  such  an  engine  would 
have  proportionately  more  power  at  the  same  number  of  revolu- 
tions, it  would  consume  proportionately  more  steam.  The  power 
of  a  crank  is  greatest  for  early  cut-offs  at  the  point  at  which  the 
valve  closes,  and  for  late  cut-offs  when  it  stands  at  right  angles 
with  the  connecting-rod,  which  point,  as  may  be  seen  from  the 
cut  on  page  175,  is  not  in  the  middle  of  the  stroke. 

An  examination  of  the  connecting-rod  of  an  engine  in  motion, 
will  show  that  the  two  ends  pass  over  different  spaces  in  a  given 
time.  If,  for  instance,  in  one  stroke  the  end  of  the  connecting- 
rod  that  is  attached  to  the  cross-head  moves  through  one  foot,  the 
end  which  is  attached  to  the  crank-pin,  and  makes  a  half  revolu- 
tion in  the  same  time,  passes  through  1*5708  feet.  Suppose  that 
an  engine  is  placed  with  its  crank  on  the  centre,  and  steam  is  ad- 
mitted ;  no  motion  will  be  produced,  and  consequently  there  will 
be  no  power  developed,  and  no  expenditure  of  steam ;  but  let  the 
piston  make  a  stroke,  the  power  exerted  is  equal  to  the  force  or 
pressure  acting  on  the  piston  multiplied  by  the  space  passed 
through,  or  it  will  be  100  foot-pounds,  assuming  the  data  previ- 
ously given.  During  the  same  time  the  crank-pin  has  passed 
through  a  space  of  1'5708  feet,  and  the  force  or  pressure  exerted 
has  been  63*66  pounds,  so  that  the  power  exerted  during  this  time, 
or  the  product  of  1.5708  multiplied  by  63*66,  is  100  foot  pounds. 


THE   ENGINEER'S  IIANDY-BOOK. 


185 


The  boss  of  the  crank  is  that  part  into  which  the  shaft  is  in- 
serted, and  which  butts  against  the  main-bearing.  In  comraon 
practice,  its  width,  when  of  cast-iron,  is  about  twice  the  diameter 
of  the  crank-shaft  journal,  and  the  width  at  the  pin  is  generally 
about  twice  the  diameter  of  the  pin.  The  section  of  the  crank  be- 
tween the  shaft  and  the  pin  is  termed  the  web ;  its  area  is  gener- 
ally equal  to  that  of  the  crank-shaft.  When  the  crank  is  round, 
it  is  called  a  crank-plate,  or  disc.  The  only  advantage  that  the 
circular  possesses  over  the  ordinary  form  is  that  it  affords  better 
facilities  for  balancing. 

Crank-Pins. 

Probably  no  part  of  the  steam-engine  more  imperatively  requires 
perfection  in  material  and  workmanship  than  the  crank-pin,  if  cool, 
noiseless  running  is  considered  desirable.  Yet  it  would  be  safe  to 
say  that  the  cranks  of  most  engines  are  so  imperfectly  fitted  as  to  be 
out  of  line  with  their  shafts.  The  most  frequent  causes  of  trouble 
with  crank-pins  are  lack  of  parallelism  between  the  pin  and  shaft, 
imperfect  material,  untrue  turning,  and  inadequate  w^earing  surface. 

It  is  generally  understood  that,  when  a  pressure  exceeding  about 
800  lbs.  per  square  inch  is  imposed  upon  a  journal,  lubrication 
with  oil  is  no  longer  adequate  to  prevent  destructive  wear.  In 
the  case  of  crank-pins  this  limit  is  frequently  approached,  and  in 
some  cases  exceeded.  Very  few  engine  manufacturers  make  their 
crank-pins  exceed  one-fourth  the  bore  of  the  cylinder  in  diameter 
and  one-third  of  it  in  length,  the  majority  being  short  of  this  pro- 
portion. 

Assuming  this  proportion,  and  that  the  rule  for  finding  the 
effective  wearing  surface  of  a  journal  is  to  multiply  its  diameter 
by  its  length,  a  little  calculation  will  show  that  the  area  of  the 
piston  exceeds  the  wearing  surface  of  the  pin  over  9y^^  times. 
Then  suppose  the  piston  to  be  subjected  to  a  pressure  of  85  lbs.  per 
square  inch,  which  is  not  unusual,  the  pressure  on  the  crank-pin 
will  be  85  X  9*4  =  799  lbs.  per  square  inch.  If  such  a  pressure 
was  constant,  it  is  very  probable  that  no  material,  perfection  of 
16^ 


186 


THE   engineer's  HANDY-BOOK. 


workmanship,  or  lubrication  would  prevent  the  heating  and  speedy 
destruction  of  the  pin  and  boxes ;  but  in  the  case  of  the  crank-pin 
such  pressures  are  but  momentary,  and  do  not  last  long  enough 
to  allow  destructive  wear  to  begin.  The  alternating  intervals  of 
no  pressure  assist  in  the  necessary  redistribution  of  the  lubricant ; 
still,  when  we  multiply  the  mean  pressure  on  the  piston  by  the 
number  of  times  that  its  area  exceeds  that  of  the  pin  (tea  times, 
in  many  cases),  the  wonder  will  be  not  that  so  many  pins  giv€. 
trouble,  but  that  so  many  do  not.  An  increase  in  the  dimensions 
of  the  pin  would,  it  is  true,  proportionately  diminish  the  pressure 
per  square  inch ;  but  the  loss  of  power,  by  the  increased  friction 
thus  induced,  would  be  equally  as  objectionable  as  the  evil  which 
it  was  intended  to  remove. 

The  length  of  a  crank-pin  should  be  equal  to  the  horse-power 
of  the  engine  divided  by  the  stroke;  the  quotient  multiplied  by 
a  coefficient  which  has  been  found  by  experiment  to  range  from 
1*3  to  1*5.  For  instance:  if  a  crank-pin  is  required  for  an  engine 
24"  X  48",  capable  of  developing  250  Hp.,  then  250  -f-  48  X  1-5 
=  7*81,  or  7|f  in.,  which  is  the  required  length. 

To  determine  whether  a  crank-pin  is  in  line  with  the  centre  of 
the  cylinder  or  not,  put  on  the  connecting-rod  and  key  the  box  up 
snug  on  the  pin ;  then  disconnect  the  rod  from  the  wrist  of  the 
cross-head  and  move  the  crank  round,  and  if  the  rod  maintains  a 
central  line  in  whatever  position  the  crank  may  be  placed,  the 
crank-pin  is  in  line  with  the  centre  of  the  cylinder.  This  test  wil> 
also  serve  to  prove  the  correctness  of  the  boring  of  the  pin-boxes 
If  they  are  not  bored  exactly  at  right  angles  to  the  centre  line  of 
the  rod,  troubles  similar  to  those  caused  by  an  untrue  pin  will 
ensue.  Another  oversight  not  generally  thought  of,  and  which 
causes  much  trouble  with  crank-pins,  is  that,  in  planing  off  the 
stub-ends  of  the  connecting-rod,  the  machinist,  through  ignorance 
or  inattention,  planes  more  off  one  side  than  the  other.  As  a  re- 
sult, every  time  the  rod  changes  its  position,  the  box  will  pinch  on 
the  crank-pin,  and  cause  undue  heating. 


THE   ENGINEER'S  HANDY-BOOK. 


187 


Crank-Shaft  Journals  and  Main-B(^arings. 

The  conditions  so  essential  in  the  manufacture  of  crank-pins, 
viz.,  good  material,  excellent  workmanship,  and  accurate  fitting, 
hold  good  also  in  the  case  of  crank-shaft  journals.  Unlike  the 
crank-pin,  steel  is  not  used  in  the  case  of  shafts,  principally  in 
consequence  of  its  extra  cost;  therefore  forged  or  rolled  iron  is  the 
material  most  generally  employed.  Since  wrought-iron  is  never 
found  perfectly  homogeneous,  the  difficulties  which  lie  in  the  way 
of  a  perfectly  true  and  cylindrical  journal  are  much  greater  than 
with  a  steel  crank-pin. 

When  the  initial  pressure  on  the  piston  is  80  lbs.  per  sq.  inch 
or  upwards,  the  diameter  of  the  crank-shaft  bearing  should  not  be 
less  than  i  the  bore  of  the  cylinder;  and,  in  order  to  prevent 
springing,  it  should  be  as  near  the  centre-line  as  possible.  Al- 
though it  will  be  impossible  to  entirely  prevent  springing,  with 
high  speed  and  initial  pressure,  yet,  by  this  arrangement,  the  lia- 
bility to  spring  may  be  very  much  diminished.  The  length  of  the 
crank-shaft  journal  should  not  be  less  than  twice  its  diameter, 
though  some  engine  builders  of  good  repute  make  them  shorter. 
The  longer  the  journal,  within  reasonable  limits,  the  more  durable 
it  will  be,  providing  the  shaft  does  not  spring,  and  is  always  per- 
fectly in  line  with  its  bearings.  But  as  these  conditions  cannot 
be  always  realized  for  any  length  of  time,  it  is  not  advisable  to 
attempt  any  greater  length  than  the  foregoing. 

As  the  pillow-block  bearing  is  not  self-adjusting,  it  is  of  great 
importance  that  it  should  be  perfectly  true  with  the  line,  so  that 
the  contact  of  the  shaft  may  be  as  nearly  even  as  possible  through- 
out. The  most  general  construction  consists  of  a  bottom  box,  side 
and  quarter  boxes,  adjusted  by  set-screws,  or  wedges  and  a  cap; 
but  the  simple  box  and  cap,  parted  at  an  angle  of  about  30°  from 
the  perpendicular,  with  its  bolts  as  short  as  possible  consistent 
with  requisite  strength,  possess  the  important  advantages  that  they 
do  not  tighten  on  the  journal  when  it  begins  to  heat,  as  is  the  case 
with  many  of  the  ordinary  forms  in  use,  and  that  at  that  angle 


188 


THE   engineer's  IIANDY-BOOK. 


the  compensation,  both  horizontal  and  vertical,  may  be  better  pro- 
vided for.  The  outer  pillow-block  bearing  being  subjected  to  less 
severe  wear,  does  not  require  the  same  care  in  its  proportions  and 
finish,  but  should  not,  for  that  reason,  be  slighted. 

Keys,  Gibs,  and  Straps. 

The  key,  gib,  and  strap  are  the  most  simple  and  effective  me- 
chanical devices  which  could  be  employed  for  securing  the  con- 
necting-rods of  steam-engines  to  the  wrist-  and  crank-pins,  and 
taking  up  the  lost  motion  in  the  boxes,  as  they  possess  sufficient 
strength  without  extra  weight  of  material,  and  facilitate  quick  and 
easy  adjustment.  There  is  quite  a  wide  difference  of  opinion  among 
builders  in  proportioning  the  keys,  gibs,  and  straps  of  their  en- 
gines. Some  make  the  thickness  of  both  straps  on  the  connecting- 
rod  ^  the  diameter  of  the  crank-pin,  and  their  width  about  |  the 
length  of  the  pin ;  while  others  make  the  width  of  their  straps 
three  times  their  thickness,  and  the  area  of  the  cross-section  at  the 
mortise  equal  to  the  area  of  the  smallest  part  of  the  connecting- 
rod  ;  while  others,  still,  make  them  equal  in  strength  to  the  weakest 
point  in  the  piston-rod,  which  they  undoubtedly  should  be  in  any 
case.  It  has  been  customary,  heretofore,  to  make  straps  thinner 
at  the  yoke  than  at  the  mortise ;  but  this  has  been  partly  aban- 
doned, as  the  amount  of  material  saved  was  insignificant,  while 
the  extra  work  was  considerable.  The  depth  of  the  gib  and  key 
in  a  good  engine  is  generally  about  three  times  their  thickness, 
and  the  taper  at  about  1  in  ten ;  though  it  ranges  all  the  way 
from  the  latter  to  1  in  24,  1  in  15  being  about  the  average.  It  is 
customary  in  some  instances,  as  in  the  case  of  marine  engines, 
locomotives,  and  other  fast-running  engines,  to  pass  a  bolt,  and  in 
some  cases  two,  through  the  stub-end  and  straps,  as  a  precaution 
against  accidents ;  the  holes  in  the  straps  being  the  exact  size  of 
the  bolt,  while  those  in  the  stub  are  slotted,  for  the  purpose  of 
admitting  of  adjustment  by  the  key  and  gib. 


THE   engineer's   HANDY-HOOK.  189 


The  Link. 

The  link-motion  is  an  arrangement  of  valve-gear  for  reversing 
engines  and  varying  the  rate  of  expansion.  It  consists  of  two 
eccentrics,  with  straps  and  rods.  The  eccentrics  are  so  placed 
that  when  one  is  in  the  right  position  for  the  engine  to  move  for- 
ward, the  other  is  in  the  position  for  moving  backward ;  and  by 
raising  or  lowering  the  link,  motion  will  be  communicated  to  the 
valve  and  the  engine  will  move  backward  or  forward.  The  re- 
sult of  this  combination  is  that  the  link  receives  a  reciprocating 
motion  in  its  centre ;  since,  when  one  eccentric  is  moving  the  end 
of  the  link  in  one  direction,  the  other  is  moving  the  other  end  in 
the  other  direction ;  so  that  the  link  will  have  nearly  the  same 
motion  communicated  to  it  as  if  it  were  suspended  from  a  pivot 
at  its  centre. 

The  horizontal  motion  communicated  to  the  link  by  the  joint 
action  of  the  eccentrics,  is  a  minimum  at  the  centre  of  its  length, 
where  it  is  equal  to  twice  the  linear  advance,  and  it  increases  to- 
wards the  extremities  of  the  various  periods  of  the  block  in  the 
link,  or  of  the  link  on  the  block,  on  the  general  principle  that 
admission  varies  with  the  travel  of  the  valve.  The  nature  of  the 
motion  derived  from  the  link  is  modified  by  the  positions  of  the 


190 


THE   ENGINEER'S  HANDY-BOOK. 


working  centres,  and  most  especially  of  the  centres  of  suspension 
and  connection.  The  centre  of  suspension  is  the  most  influential 
of  all  in  regulating  the  admission,  and  its  transition  horizontally 
is  much  more  efficacious  than  a  vertical  change  of  place  to  the 
same  extent,  inasmuch  as  the  vertical  movement  of  the  body  of 
the  link,  with  the  consequent  slip  between  the  link  and  the  block, 
is  the  least  possible  when  the  suspended  centre  lies  in  the  centre 
line  of  the  link,  and  increases  as  the  centre  is  moved  laterally. 
The  centre  line  of  the  link  is  therefore,  in  this  respect,  the  most 
favorable  location  for  the  suspension,  even  though  it  be  not  always 
practicable  for  equal  admissions. 

The  amount  of  travel  communicated  to  the  valve  depends  upon 
the  distance  the  block  is  from  the  centre  of  the  link.  By  moving 
the  link  up  or  down  on  the  block,  the  travel  of  the  valve  will 
either  be  increased  or  decreased ;  and  since  the  travel  of  the  valve 
is  the  measure  of  the  lap,  to  reduce  the  travel  is  tantamount  to 
increasing  the  lap,  and  also  the  lead.  Thus  the  link-motion  be- 
comes an  expedient  for  regulating  the  amount  of  expansion  with 
which  the  engine  works.  Though  it  may  be  claimed  by  some 
that  cutting  off  by  the  link  has  a  tendency  to  affect  the  exhaust, 
it  does  not  do  so  to  any  injurious  extent,  as  the  later  opening  of 
the  exhaust  is  a  positive  advantage,  as  it  balances  the  resistance 
due  to  the  early  admission  of  the  steam  at  the  other  end,  before  the 
engine  has  reached  the  end  of  the  stroke.  It  will  be  seen,  for  the 
foregoing  reasons,  that  the  link  is  a  perfect  expansion-gear,  as, 
when  in  full  stroke,  it  is  superior,  in  many  respects,  to  most  other 
cut-off  devices,  since,  while  the  lead  is  increased  as  the  travel  of 
the  valve  is  decreased,  or,  in  other  words,  as  the  link  is  lifted  to- 
wards the  centre,  and  the  supply  of  steam  cut  off  at  an  earlier 
point  in  the  stroke,  the  lead  becomes  a  positive  advantage,  as  it 
serves  as  a  cushion  to  the  piston  when  its  reciprocating  motion  is 
rapid,  as  is  frequently  the  case. 

The  ease  and  facility  with  which  the  link  may  be  handled  is 
another  very  important  feature  in  its  favor.  In  fact,  what  could 
we  do  without  it  when  handling  engines,  especially  large  locomo- 


THE   ENGINEER'S  HANDY-liOOK. 


191 


tives  or  marine  engines,  which  have  of  necessity  to  run  backwards 
with  the  same  ease,  speed,  and  facility  as  they  run  ahead?  The 
link  is  a  splendid  mechanical  conception,  and  one  of  the  greatest 
improvements  that  has  ever  been  made  in  the  locomotive,  marine 
engine,  or  any  other  class  of  motors  requiring  a  reversing  gear. 

The  radius  of  the  link  is  the  distance  from  the  centre  of  the 
driving-axle,  or  shaft  on  which  the  eccentric  is  located,  to  the 
centre  of  the  link ;  while  the  link  itself  is  a  segment  of  the  circle 
of  that  diameter.  The  length  may  be  longer  or  shorter ;  but  any 
variation  from  these  proportions  will  give  more  lead  at  one  end 
than  at  the  other  while  working  steam  expansively ;  but  the  ra- 
dius may  be  several  inches  shorter  or  longer,  without  materially 
affecting  the  motion.  The  vital  point  in  designing  a  valve  link- 
motion  is  the  point  of  suspension  of  the  link.  If  it  is  suspended 
from  the  centre,  it  will  invariably  cut  off  steam  sooner  in  the 
front  stroke  than  in  the  back  stroke,  while  working  expan- 
sively. 

The  nearer  the  block  is  brought  to  either  end  of  the  link,  the 
greater  will  be  the  travel  of  the  valve,  and  the  more  the  steam 
and  exhaust  will  be  opened.  The  term  "  full-gear  forward  means 
that  the  link  is  dropped  to  its  full  extent ;  while  "  full-gear  back- 
ward means  that  the  link  is  lifted  to  its  full  extent.  When  the 
link-block  stands  directly  under  the  saddle-plate,  both  ports  are 
closed,  and  neither  admission  nor  exhaust  can  take  place.  The 
distance  between  the  block  and  the  end  of  the  link  when  in  full- 
gear  is  termed  the  clearance. 

In  the  Walschaert  link-motion,  which  was  used  on  one  or  two 
of  the  small  engines  at  the  -Centennial  Exposition,  the  mid-gear 
movement  was  derived  directly  from  the  cross-head,  while  the  end, 
or  full-gear,  movement  was  derived  from  a  single  eccentric,  or  a 
return  crank,  from  the  main  crank-pin.  The  middle  of  the  link 
IS  stationary,  and,  of  itself,  imparts  no  motion  to  the  valve ;  but 
between  the  link  and  valve  is  an  arrangement  for  imparting  a 
reduced  and  reversed  copy  of  the  piston  movement  to  the  valve, 
which  movement,  being  always  present,  modifies  that  of  the  ec- 


192 


THE   engineer's  HANDY-BOOK. 


centric  at  all  points,  giving  it  the  effect  of  angular  advance,  which 
is  not  given  to  the  eccentric  in  the  case  of  the  ordinary  link-mo- 
tion. 

Lifting  and  stationary  links.  —  The  lifting-link  is  raised  and 
lowered  to  effect  the  changes  it  is  designed  to  perform ;  while  in 
the  stationary  link  the  block,  instead  of  the  link,  is  shifted.  In 
the  stationary  link  but  one  eccentric  is  generally  used,  the  throw 
of  which  corresponds  to  the  middle  of  the  ordinary  link  ;  for  this 
reason,  more  mischief  would  be  caused  by  any  lost  motion  in  the 
eccentric  straps  or  other  connections.  Moreover,  it  does  not  allow 
of  ready,  independent  adjustment  of  the  backward  and  forward 
motion  in  full  gear. 

Fly-Wheels. 

The  object  of  the  fly-wheel  is  to  equalize  the  motion  whenever 
either  the  power  communicated  or  the  resistance  to  be  overcome 
is  variable.  In  the  one  case,  the  fly-wheel  may  be  said  to  be  a 
distributor  of  power.  The  complicated  impulses,  acting  on  the 
mass  in  motion,  preserve  the  momenta,  without  disturbing  the 
regularity  of  movement.  The  effect  of  one  impulse  is  so  absorbed 
or  distributed  in  the  momentum  of  the  wheel,  that  it  may  be  said 
to  have  hardly  been  diminished  before  the  next  impulse  is  re- 
ceived. 

In  the  other  case,  or  where  the  fly-wheel  is  used  to  overcome  a 
variable  resistance,  it  may  be  considered  a  conservator  of  power. 
The  power  having  been  exerted  in  getting  up  the  speed,  is  retained 
in  the  moving  mass,  and  the  whole  of  the  powder  expended,  with  the 
exception  of  that  which  has  been  lost  through  friction  and  resist- 
ance of  the  air,  can  be  brought  to  bear  at  any  instant  upon  the 
resistance  to  be  overcome.  When  the  crank  and  connecting-rod 
are  in  one  straight  line,  as  they  must  be  twice  in  each  revolution, 
the  crank  is  said  to  be  on  its  dead-centre,  because  there  the 
force  of  the  piston  is  dead  or  ineffective.  It  is  evident  that,  when 
the  crank  is  at  right  angles  to  the  connecting-rod,  the  latter  is 
exerting  the  maximum  of  power;  but  when  the  forward  or  back- 


Tin:  engineer\s  handy-book.  193 


ward  dead-centre  is  reached,  the  crank  would  remain  there,  hut 
for  the  action  of  the  fly-wheel,  which,  by  its  accumulated  momen- 
tum, carries  it  over  the  dead-centre. 

Thus,  through  the  momentum  of  the  fly-wheel,  no  perceptible 
variation  occurs  in  the  velocity  of  the  engine  ;  the  unequal  le- 
verage of  the  connecting-rod  is  corrected,  and  a  steady  and  uni- 
form motion  produced.  The  fly-wheel,  as  before  stated,  is  a 
regulator  and  reservoir,  and  not  a  creator  of  motion.  The  ac- 
cumulated velocity  in  the  fly-wheel,  where  the  motion  is  required 
to  be  excessively  equable,  should  be  about  six  times  that  of  the 
engine  when  the  crank  is  horizontal.  As  regularity  of  motion  is 
of  much  greater  importance  in  some  cases  than  in  others,  the 
weight  and  diameter  of  the  fly-wheel  must  depend  on  the  work 
and  the  character  of  the  machinery  it  is  intended  to  drive ;  so 
that,  in  proportioning  a  fly-wheel  to  a  given  engine,  attention  must 
be  paid  to  many  particular  circumstances  rather  than  to  any  given 
rule.  There  are  circumstances  in  which  the  use  of  a  fly-wheel 
may  be  dispensed  with,  as  where  a  pair  of  engines  work  side  by 
side,  whose  cranks  are  at  different  angles,  so  that  one  assists  the 
other  to  pass  the  centres,  or  where  smoothness  of  motion  is  not  an 
absolute  necessity. 

Rule  for  finding  the  proper  weight  of  the  fly-wheels  of  steam- 
engines. 

Divide  the  constant  number  7,000,000  by  the  square  of  the 
number  of  revolutions  per  minute,  and  by  the  diameter  of  the 
wheel  in  feet.  The  quotient  will  be  the  number  of  pounds  per 
horse-power  required  in  the  rim  of  the  wheel. 

The  above  rule  is  correct,  so  far  as  it  recognizes  the  fact  that 
the  efficacy  of  a  fly-wheel  increases  with  the  square  of  its  velocity 
and  with  its  diameter.  The  constant  number  is  found  by  taking 
some  engine  whose  fly-wheel  is  known  to  be  right  at  a  given  load, 
dividing  its  weight  by  the  horse-power  developed,  and  multiplying 
the  quotient  by  the  square  of  the  number  of  revolutions  per  min- 
ute, and  by  the  diameter.  When  so  found,  it  will  give  correct 
results  for  all  other  engines  of  the  same  class  doing  similar  work. 
17  N 


194         THE  engineer's  handy-book. 

This  constant  number  must  not,  however,  be  regarded  as  arbi- 
trarily fixed.  It  will  give  the  weight  of  the  wheels  near  enough 
for  automatic  cut-off  engines. 

The  Watertown  Automatic  Cut-Off  Engine. 

The  cut  on  the  opposite  page  represents  the  Hampson  Auto- 
matic Cut-Off  Engine,  the  bed-plate  of  which,  as  will  be  observed, 
is  of  the  box  pattern ;  the  metal  in  which  is  so  distributed  as  to 
combine  strength,  stiffness,  and  rigidity,  without  extra  weight. 
The  steam-cylinder  and  main  pillow-block  and  guides  are  at- 
tached to  the  bed-plate  in  such  a  manner  as  to  prevent  the 
possibility  of  becoming  loose  when  the  engine  gets  out  of  line. 
As  the  steam-chest  is  the  full  length  of  the  cylinder,  with  the 
ports  opening  directly  from  it  into  the  clearance,  it  enhances  the 
value  of  these  engines  very  much,  as  it  obviates  the  waste  induced 
by  long  steam-ports. 

The  valve-geap  receives  its  motion  from  two  eccentrics  on  the 
main  shaft,  the  one  next  the  pillow-block  being  connected  with 
the  main  valve,  which  is  an  ordinary  slide-valve,  with  this  ex- 
ception —  that  the  steam,  instead  of  passing  in  at  the  ends  of  it, 


Pi^.  1. 


enters  through  it  by  means  of  ports,  as  shown  at  C  D,  Fig.  1. 
H  represents  the  back  of  the  main  valve,  which  is  also  the  seat 


THE   ENGINEER'S    HANDY-BOOK,  195 


196 


THE    ENGINEER'S  HANDY-BOOK. 


of  the  cut-off  valve,  G,  F  represents  the  stem  of  the  main  valve, 
and  B  the  stem  of  the  cut-off  valve,  which  is  continued  on  through 
the  end  of  the  steam-chest,  and  is  held  steady  when  the  engine  is 
working  by  means  of  a  horn  at  A,  The  reader  will  notice  that 
there  is  a  rack  cut  in  the  back  of  the  cut-off,  which  engages  the 
teeth  of  a  small  wheel  on  the  valve-stem,  and  from  this  device  any 
one  would  soon  come  to  the  conclusion  that  the  adjustment  of  the 
cut-off  is  accomplished  by  rolling  the  valve-stem.  This,  as  a  matter 
of  course,  will  raise  and  lower  the  cut-off  valve  by  means  of  the 
rack  and  pinion,  thereby  opening  the  ports. 

The  governop,  which  is  very  powerful  and  sensitive,  embodies 
some  peculiarities  of  design  and  construction  not  common  in  govern- 
ors, inasmuch  as  the  point  of  suspension,  instead  of  being  on  the  same 
side  of  the  spindle  as  the  ball,  is  carried  over  to  the  opposite  side,  * 
thereby  greatly  increasing  its  power  and  sensitiveness.  Directly 
under  the  governor  there  is  a  disc  on  the  valve-stem,  with  teeth  • 
cut  on  the  periphery  about  half  the  circumference,  and  these  teeth 
engage  a  rack  connected  with  the  governor-spindle.  Consequently, 
as  the  balls  of  the  governor  rise  and  fall,  a  proportional  movement 
will  be  transmitted  to  the  cut-off  valve.  To  determine  the  point 
at  which  the  engine  is  cutting  off  when  running,  the  plain  part  of 
the  disc,  which  is  connected  with  the  governor  and  valve-stem,  has 
marks  and  figures  upon  it,  each  mark  indicating  a  point  in  the 
length  of  the  stroke.  There  is  a  point  which  coincides  with  these 
marks,  and  can  be  seen  under  the  pulley  attached  to  the  governor. 
To  increase  or  diminish  the  speed,  a  counterweight  is  attached  to 
the  end  of  the  governor-spindle,  under  the  steam-chest. 

These  engines  possess  many  excellent  features.  The  bearings 
are  well  proportioned  and  all  the  parts  thoroughly  fitted ;  the 
fly-wheels  are  turned  on  the  face  and  sides  and  accurately  bal- 
anced ;  the  connecting-rod  and  crank-shafts  are  made  of  the  best 
hammered  wrought-iron  ;  the  crank-  and  wrist-pins  are  made  of 
steel ;  the  connecting-rod  boxes  of  gun-metal,  and  the  main-bear- 
ings lined  with  the  best  anti-friction  metal ;  while  the  cylinder  is 
cast  of  car-wheel  iron,  and  jacketed  to  prevent  radiation. 


THE   engineer's  HANDY-BOOK. 


197 


Steam-Engine  Governors. 

The  subject  of  regulating  the  speed  of  steam-engines,  and 

more  especially  those  which,  from  circumstances  and  the  nature 
of  the  work  to  be  performed,  are  liable  to  constant  change,  has  of 
late  years  received  no  little  attention  from  engineers  and  practical 
inventors,  and  as  a  result  various  kinds  of  governors  have  been 
introduced.  It  would  be  safe  to  say  that  this  device  has  absorbed 
more  thought,  and  re- 
ceived more  attention 
on  the  part  of  mechan- 
ics, than  any  other  ad- 
junct of  the  steam-en- 
gine. In  the  ordinary 
governor,  the  principal 
part  of  the  apparatus 
consists  of  a  pair  of 
balls  revolving  round 
a  vertical  axis  or  spin- 
dle driven  by  a  train 
of  .mechanism,  gener- 
ally mitre-gears,  which 
causes  their  angular  ve- 
locity of  revolution  to 
bear  a  fixed  ratio  to  the 
velocity  of  the  prime 
mover.  The  rods  of 
the  pendulums  place 
themselves  at  an  an- 
gle with  the  vertical 
axis,  so  that  the  common  height  of  the  pendulums  is  that  corre- 
sponding to  the  number  of  turns  in  a  second.  The  regulator  must 
be  so  adjusted  as  to  be  in  the  proper  position  for  supplying  the 
proper  amount  of  power  when  the  pendulum-rods  are  at  the  angle 
of  inclination  corresponding  to  the  proper  speed  of  .the  machine^ 
17* 


The  Waters  Governor. 


198 


THE   ENGINEER'S  HANDY-BOOK. 


When  the  speed  deviates  above  or  below  that  amount,  the  out- 
ward or  inward  motion  of  the  pendulum-rods  acts  on  the  spindle, 
so  as  to  open  the  valve  when  the  speed  is  too  low,  and  close  it 
when  it  is  too  high. 

In  the  attainment  of  this  object,  the  principle  of  centrifugal 
force,  as  embodied  in  the  old  fly-ball  governor  of  Watt,  has  been 
more  resorted  to  than  any  other;  but,  aside  from  this,  the  governor 
has  been  so  improved,  altered,  and  reconstructed,  since  his  time, 
as  to  be  almost  unrecognizable ;  but  still  the  old  principle  is 
there,  and  also  the  three  prominent  defects  which  so  materially 
interfere  with  its  efficiency.  The  first  of  these  is  friction  which 
arises  from  the  joints,  and  is  caused  by  swinging  the  balls  or 
weights  by  the  short  end  of  the  arm  or  lever  to  which  they  are 
attached.  The  second  defect  is  due  to  the  fact  that  the  balls,  as 
they  assume  different  positions  in  keeping  with  the  speed  with 
which  they  revolve,  are  obliged  to  rise  or  fall.  This  is  necessary 
in  order  that  the  resistance  which  the  weights  offer  to  centrifugal 
force  should  constantly  increase;  if  it  did  not  so  increase,  the 
weights,  when  once  started  from  their  position  of  rest,  would  in- 
stantly go  to  the  extreme  limit  of  motion.  The  rising  of  the  balls 
shortens  the  distance  which  they  are  allowed  to  move  for  a  given 
variation  by  bringing  the  centres  of  ball  and  *arm  on  which  they 
swing  into  a  straight  line,  so  that  a  variation  which  moves  the 
balls  a  given  distance  upward,  if  it  occurs  again,  will  not  move 
them  nearly  so  far  in  the  same  direction.  Again,  the  same  force 
that  would  support  the  balls  in  any  plane  would  not  raise  them 
to  that  plane  from  a  lower  one.  So  between  friction,  which  de- 
stroys the  delicate  power  that  the  balls  assume  under  a  slight 
change,  and  the  necessity  for  a  large  change  to  overcome  their 
inertia,  it  is  almost  impossible  to  attain  a  degree  of  regulation 
which  would  be  equal  to  all  requirements. 

Governors  when  attached  to  throttle- valves  work  under  cir- 
Tjumstances  that  necessitate  the  use  of  openings  for  the  passage  of 
the  steam  that  are  too  small  in  area,  so  much  so  that  the  useful 
effects  of  the  steam  are  considerably  diminished.  On  this  depends 


THE   engineer's  HANDY-BOOK. 


199 


the  ill  repute  of  throttling  engines  as  compared  with  those  which 
regulate  by  governor  controlled  valve  motions  or  variable  cut-off. 
If  the  valve  of  a  governor  has  too  large  openings,  it  will,  owing 
to  the  unsteady  action  of  the  governor,  admit  too  large  a  quantity 
of  steam,  and  cause  a  jumping  of  the  engine;  then,  m  trying  to 
shut  off  this  extra  amount,  it  shuts  it  all  off;  in  fact,  the  governor 
cannot  fix  it  exactly  right,  being  incapable  of  delicate  changes. 
This  difficulty  is  best  met  by  making  the  openings  in  the  valve 
of  peculiar  shape,  so  that  they  open  and  close  in  a  ratio  different 
from  that  of  the  governor.    With  a  governor  that  would  run  per- 
fectly up  to  theory,  and  be  steady  and  capable  of  taking  a  posi- 
tion  in  keeping  with  the  speed, 
and  not  leaving  it  without  a 
change  in  speed,  ,  a  very  large 
area  might  be  used,  and  the 
useful  effects  of  the  steam  would 
not  be  impaired,  neither  would 
there  exist  a  necessity  for  great 
changes  in  speed  to  get  the  re- 
quired opening  and  closing  of 
the  valve.    The  extra  amount 
of  steam  required  to  drive  a 
heavy  addition  of  load  on  an 
engine  is   surprisingly  small, 
provided  that  the  engine  can  get 
the  steam  at  the  very  instant  the 
load  is  applied,  and  before  the 
momentum  of  the  machinery 
becomes  much   reduced;  but 
let  the  engine  once  get  below 
speed,  the  circumstances  will 
be  very  different,  as,  even  with- 
out any  load,  the  engine  would  take  some  time  to  come  to  speed. 

The  third  defect  in  governors  on  throttling  engines  is  that  the 
spindle  or  valve-stem  has  of  necessity  to  pass  through  steam-tight, 


The  Shive  Governor. 


200 


THE   engineer's  HANDY-BOOK. 


packing'  or  stuffing-boxes,  which  have  to  be  screwed  up  to  pre- 
vent leakage,  without  any  guide  save  the  judgment  of  the  en- 
gineer, which  increases  the  friction  and  interferes  with  the  free 
action  of  the  governor.  There  is  also  the  friction  on  the  governor- 
valve  necessary  to  overcome  the  power  required  to  move  the 
valve-stem  through  all  its  bearings,  stuffing-boxes,  guides,  etc., 
under  the  pressure  of  steam.  Were  it  possible  to  construct  a 
governor  for  throttling  engines  which  would  approach  in  practice 
what  theory  would  demonstrate,  the  fly-ball  or  centrifugal  gov- 
ernor would  be  a  perfect  regulator;  but  this  appears,  according  to 
mechanical  laws,  to  be  impossible.  By  the  use  of  isochronous 
governors,  which  would  not  admit  of  any  variation  of  speed,  but 
would  be  in  equilibrium  at  any  speed,  whether  the  balls  were  up 
or  down,  or  in  any  other  position,  the  defects  of  the  common  gov- 
ernor were  supposed  to  be  obviated;  but  it  was  found  by  expe- 
rience that  power  and  stability  were  necessary,  and  isochronism 
in  its  strict  sense  unattainable. 

The  economy  of  a  good  governor  has  rarely  been  appreciated 
by  owners  of  steam-engines  and  steam-users.  Experience  has 
shown  the  speed  best  adapted  for  each  and  every  process  in  the 
manufacturing  and  mechanical  arts,  and  the  governor  that  fails 
to  meet  all  the  varied  requirements  of  each  process  is  of  no  value 
in  an  economical  point  of  view.  Every  stroke  which  an  engine 
makes  below  its  regular  speed  increases  the  cost  of  production, 
and  every  stroke  above  it  is  a  waste  of  steam,  and  consequently 
of  fuel.  If  an  engine  is  geared  to  run  at  80  revolutions  per 
minute,  when  a  heavy  piece  of  machinery  is  thrown  off*,  the 
governor  admits  of  an  increase  of  speed  of  from  10  to  15  revolu- 
tions per  minute.  This  incurs  a  waste  of  power,  and  consequently 
a  waste  of  from  12  to  20  per  cent,  of  fuel.  On  the  other  hand, 
when  a  heavy  piece  of  machinery  is  thrown  on,  the  governor 
allows  the  engine  to  lag  behind  its  regular  speed  by  from  10  to  15 
strokes  per  minute;  this  increases  the  cost  of  production.  If  a  gov- 
ernor is  unreliable,  it  is  worthless;  if  reliable,  its  first  cost  is  merely 
a  nominal  consideration.    There  are  many  processes,  such  as  mill- 


THE   engineer's  HANDY-HOOK. 


201 


ing,  weaving  delicate  fabrics,  printing  from  small  type,  or  the  very 
accurate  turning  of  fine  material,  where  a  good  governor  is  of 
immense  value.  Unfortunately  for  the  progress  of  the  mechanical 
arts,  no  governor  yet  invented  has  met  all  the  necessary  require- 
ments, or  the  varied  circumstances  under  which  they  are  employed. 

Governors  are  sometimes  attached  to  marine  engines  for  the 
purpose  of  equalizing  the  revolutions  in  heavy  sea-ways,  and  pre- 
venting the  engines  from  racing,  which  is  caused  by  an  insufficient 
immersion  of  the  paddle-wheels  or  propellers,  and  which  may  be 
ascribed  either  to  the  lightness  of  the  load  or  the  heavy  swell 
of  the  sea.  But  from  whatever  cause  racing  may  occur,  it  is 
always  attended  with  danger,  as  the  undue  strain  to  which  the 
machinery  is  subjected  is  liable  to  result  in  a  breakdown.  Marine 
governors  have  not  proved  a  success  up  to  the  present  time,  nor 
has  any  one  yet  been  invented  which  may  be  adapted  to  all  classes 
of  marine  engines. 

Governors  should  be  kept  perfectly  clean  and  free  from  accu- 
mulations induced  by  the  use  of  inferior  oil,  as  such  gummy  sub- 
stances have  a  tendency  to  interfere  with  the  easy  movement  of 
the  diflferent  parts.  Many  first-class  regulators  have  been  con- 
demned as  not  being  capable  of  controlling  the  engine  at  a  uniform 
speed,  when  all  that  was  required  was  a  good  cleaning. 

Governor-spindles  working  through  stuffing- boxes  should  be 
frequently  and  carefully  packed,  as,  when  the  packing  becomes 
old  and  dry,  if  screwed  up  to  prevent  leakage,  it  interferes  with 
the  free  action  of  the  governor. 

Rules  for  calculating  the  size  of  pulleys  for  governors. — To  find 
the  diameter  of  the  governor  shaft-pulley.  Multiply  the  number  of 
the  revolutions  of  the  engine  by  the  diameter  of  the  engine  shaft- 
pulley,  and  divide  the  product  by  the  number  of  revolutions  of 
the  governor. 

To  find  the  diameter  of  the  engine  shaft-pulley,  —  Multiply  the 
number  of  revolutions  of  the  governor  by  the  diameter  of  the 
governor  shaft-pulley,  and  divide  the  product  by  the  number  of 
revolutions  of  the  engine. 


202 


THE   ENGINEER'S  HANDY-BOOK. 


How  to  Balance  the  Reciprocating  and  ReyoMng  Parts  of 
Vertical  Engines. 

If  the  counterweight  be  so  arranged  as  to  describe  a  circle  of 
the  same  radius  as  that  of  the  crank-pin,  it  must  be  as  heavy  as 
the  piston,  connecting-rod,  and  crank-pin  ;  but  if  it  has  a  greater 
circle  than  that  of  the  crank-pin,  it  may  weigh  less  than  the 
piston  and  its  connections  ;  the  only  material  condition  being,  that 
the  momentum,  or  amount  of  mechanical  power  resident  in  the 
counterweight  when  moving  in  one  direction,  shall  balance  the 
momentum  of  the  piston  and  its  connections  when  moving  in  the 
opposite  direction. 

When  a  vertical  engine  runs  slow,  the  weight  of  the  piston 
and  piston-rod,  cross-head,  connecting-rod,  and  crank-pin  must  be 
counterbalanced  so  that  it  will  stand  still  in  any  position ;  but 
when  the  speed  is  very  high,  it  is  necessary  to  counterbalance 
only  such  parts  as  revolve  round  the  centre  of  the  shaft,  the  crank- 
pin,  the  stub-end,  and  half  the  connecting-rod.  It  is  customary 
to  give  more  steam-lead  on  the  valve  at  the  bottom  than  at  the 
top  of  the  cylinder  in  order  to  compensate  for  the  weight  of  the 
piston.  • 

Heating  in  Journals  and  Reciprocating  Parts  of  Steam- 

Engines. 

Heating  in  the  journals  and  reciprocating  parts  of  steam- 
engines  may  be  attributed  to  the  following  causes :  bad  proportion, 
improper  fitting,  unsuitable  material,  want  of  homogeneity  between 
the  materials  of  which  the  journals  and  bearings  are  composed, 
the  reciprocating  or  revolving  parts  being  out  of  line,  the  boxes 
being  screwed  down  or  keyed  up  too  tight,  dirt,  sand,  or  grit  get- 
ting into  the  journals,  want  of  proper  lubrication,  etc.  The  last 
mentioned  cause  is  much  more  complicated  than  would  at  first 
sight  appear,  as  there  are  many  conditions  to  be  taken  into  con- 
sideration, among  which  may  be  enumerated  weight  of  load,  area 
of  surface  subjected  to  pressure,  velocity  of  movement,  etc. 


THE   ENGINEER'S  HANDY-BOOK. 


203 


Reversing-Gear  for  Marine  Engines. 

In  the  early  days  of  the  steam-engine,  the  only  reversing- 
gear  in  use  was  the  V  hook,  which  was  very  imperfect,  uncertain, 
and  unreliable  in  action  and 
difficult  of  adjustment,  and, 
in  consequence  of  its  action 
being  positive,  steam  could 
not  be  worked  expansively 
on  engines  on  which  it  was 
employed.  A  more  modern 
arrangement  was  the  loose 
eccentric,  which,  in  conse- 
quence of  the  eccentric-hook 
being  thrown  out  of  gear, 
moved  half-way  round  on  the 
shaft  whenever  it  became 
necessary  to  reverse  the  en- 
gine. The  most  perfect  re- 
versing and  expansion  gear 
ever  employed  in  connection 
with  the  steam-engine  is  the 
link. 

A  A  shows  the  bed-plate; 
B,  the  pillow-block  bearing; 
Z),  the  shaft;  EE,  the  eccen- 
tric-rods ;  C,  the  connecting-rod ;  the  link ;  G,  the  cross-head 
wrist;  J,  the  bonnet  of  steam-chest;  I the  steam-cylinder;  K, 
the  cylinder-head  ;  L,  the  steam-pipe  ;  J/,  the  front  column  which 
supports  the  cylinder ;  JV,  the  reach-rod ;  0,  the  reverse  arm  of 
the  bell-crank  by  which  the  link  is  moved  back  and  forth ;  P,  the 
lifting  arm ;  JB,  the  screw  by  means  of  which  the  link  is  reversed ; 
S  Sy  the  guides  through  which  the  spindle  of  the  screw,  i?,  moves ; 
Q,  the  hand- wheel  by  which  the  lifting  arm,  P,  is  moved  up  or 
down  for  the  purpose  of  changing  the  position  of  the  link. 


204 


THE  ENGINEEk's  HANDY-BOOK. 


THE   engineer's  HANDY-BOOK. 


205 


The  Slide-Valve. 

The  function  of  the  common  slide-valve  is  to  admit  steam  to 
the  piston  at  such  times  when  its  force  can  be  usefully  expended 
in  propelling  it,  and  to  release  it  when  its  pressure  in  the 
cylinder  is  no  longer  required.  Notwithstanding  its  extreme 
simplicity  as  a  piece  of  mechanism,  no  part  of  the  engine  is  more 
puzzling  to  the  average  engineer  when  the  problem  to  be  solved 
is  to  determine  beforehand  the  results  which  will  be  produced 
by  a  given  construction  and  adjustment,  or  the  proportions  and 
adjustment  required  to  produce  given  results.  All  who  have  had 
any  experience  in  constructing  and  setting  slide-valves  are  aware, 
in  a  general  way,  that  the  events  of  the  stroke  cannot  be  inde- 
pendently adjusted;  that,  for  instance,  a  cut-off  earlier  than  about 
three-fourths  of  the  stroke  can  only  be  had  at  the  expense  of  more 
or  less  distortion  of  the  other  events,  and  that  for  some  reason,  not 
always  apparent,  it  is  impossible  to  completely  equalize  the  events 
gf  the  two  strokes,  occurring  during  one  revolution. 

But  hitherto  no  simple  means  have  been  given  by  which  to  de- 
termine exactly  the  degree  in  which  a  given  change  in  any  event 
affects  the  rest.  There  is  no  lack  of  literature  on  the  subject,  but 
the  manner  in  which  it  is  generally  treated  is  calculated  to  be- 
wilder the  average  reader  more  than  to  assist  him  ;  to  invest  the 
subject  with  additional  difficulties  rather  than  to  simplify  it.  The 
manner  in  which  the  slide-valve  performs  its  functions  cannot  be 
at  once  perfectly  shown  without  the  aid  of  a  working  model,  but 
a  considerable  step  may  be  taken  in  this  direction  by  the  con- 
struction and  study  of  diagrams  similar  to  the  following.  It 
should  be  understood,  however,  that  the  measurements  given  of 
lead,  cut-off,  compression,  etc.,  are  only  approximately  correct ;  the 
object  being  to  give  the  methods  by  which  correct  results  may  be 
obtained  rather  than  the  results  themselves. 

Fig.  I,  page  207,  represents  the  position  of  the  piston  and  valves 

Iat  the  beginning  of  the  stroke,  when  the  latter  is  just  commencing 
to  open.    The  motion  of  both,  as  will  be  observed,  is  to  the  left. 
18 


206 


THE   ENGINEEK'S  HANDY-BOOK. 


Fig.  2  shows  the  relative  position  of  the  piston  and  valve 
at  about  i  of  the  stroke ;  supposing  the  travel  to  be  equal  to  the 
sum  of  the  width  of  both  steam-ports  and  the  steam-lap  at  both 
ends,  so  that  the  ports  will  be  just  opened  full  for  the  steam,  the 
valve  will  be  moving  to  the  left.    When  the  piston  reaches  the 
left  end  of  its  stroke,  the  valve  will  have  moved  to  the  right  till 
it  begins  to  admit  steam,  at  the  left  hand  end,  just  as  Fig.  1  shows 
the  admission  taking  place  at  the  other  end,  and  during  the  return 
stroke,  the  conditions  represented  by  Figs.  2  and  3  will  follow  in 
succession,  at  nearly  corresponding  points  in  the  travel  of  the 
pistons.    If  the  piston  was  connected  to  the  crank  by  means  of  a 
slotted  yoke,  the  events  of  the  two  strokes  would  occur  at  exactly 
corresponding  points  in  the  travel  of  the  piston,  but  the  connecting- 
rod  unavoidably  introduces  a  certain  amount  of  distortion,  the 
nature  and  extent  of  which  will  be  explained  hereafter.    Fig.  3 
shows  the  position  of  the  valve  at  mid-travel,  or  when  if  of 
the  stroke  is  complete.    The  compression  at  the  left  end  towards 
which  the  piston  is  moving  has  just  commenced,  and  the  exhaust 
is  about  to  take  place  from  the  other  end.  The  events  which  occur 
in  connection  with  the  slide-valve,  viz.,  admission,  suppression,  re- 
lease, and  compression,  may  be  explained  as  follows:  — To  find 
the  cut-off,  exhaust,  exhaust-closure,  port-openings,  and  angular 
advance  which  will  be  produced  by  a  given  lap,  lead,  and  valve- 
travel,  the  lead  and  laps  being  equal  at  the  two  ends.  Suppose 
the 'data  to  be  as  follows  :  valve-travel  2|  in.,  lap  j%  lead  m, 
stroke  of  engine  24  inches.  _ 

Draw  the  circle  AFB  (?,  etc.,  the  diameter  of  which  may, 
when  tlie  engine  is  of  considerable  size,  be  equal  to  the  travel  of 
the  valve,  as  in  the  present  case.  Draw  the  line  A  B  through 
the  centre  of  the  circle,  continuing  it  beyond  5  to  a  distance 
nearly  equal  to  three  times  the  distance  A  B.  With  the  given 
lap  in  the  compasses,  draw  short  arcs  of  circles  at  D  and  E  from 
the  centre,  C.  Draw  lines  a  6  and  e  d,  parallel  to  each  other, 
touching  the  arcs  D  and  E,  equidistant  from  the  intersections  ot 
the  line  A  B,  with  the  circle  equal  to  the  given  lead,    bet  the 


THE   ENGINEEr\s  HANDY-BOOK. 


207 


compasses  to  a  distance  which  will  be  to  -4  jB  as  the  connecting- 
rod  is  to  the  stroke  of  the  engine,  which  in  the  present  case  is 
about  7i  in. ;  and  with  the  foot  in  the  continuation  of  the  line  A 
By  draw  arcs  b  e  and  df,  which  will  locate  the  points  of  cut-off,/ 
aifd  e  on  line  A  B,  which  represents  the  stroke  of  the  engine  as 
well  as  the  travel  of  the  valve.  By  constructing  and  applying  a 
scale,  such  as  Fig.  1,  in  which  the  travel  of  the  valve  is  divided 


L 


I  I  I  1  f  I  M  h  t    M  I  [  I  I  I  1  I  I  I 
3      6      9      12     15     18    21  24 

Fig.  1. 


into  as  many  parts  as  there  are  inches  in  the  stroke  of  the  piston, 
1  it  is  found  that,  as  the  piston  moves  from  the  shaft,  the  cut-off,  e, 
I  takes  place  at  18|  inches  from  Ay  and  the  other,  /,  at  19|  inches 

from  By  making  an  inequality  of  li  inches. 

If  the  valve  has  no  exhaust-lap  at  either  end,  working  "line  oc 


208 


THE   engineer's  HANDY-BOOK. 


line,"  as  it  is  sometimes  called,  draw  line  k  I  through  the  centre 
C,  and  parallel  to  a  6  and  c  d,  and  from  ^  and  ^  draw  arcs  k  h 
and  /  as  directed  for  the  arcs  d  f  and  b  e,  which  will  locate  the 
points  of  exhaust  and  exhaust-closure  at  h  and  g,  about  lA  and 
inches  respectively  from  the  ends  of  the  stroke.  A  represents 
the  end  of  the  stroke  nearest  the  crank  ;  and  it  will  be  observed 
that  the  events  occurring  nearest  that  end  are  later  in  the  stroke 


L 


A 

/  ^\ 

yy 

9 \b 

a' 

IT 

Fig.  2. 


than  corresponding  events  at  the  other  end,  which  will  always  be 
the  case  when  the  laps  are  equal  at  the  two  ends  of  the  valve. 
The  port-openings  will  he  D  F  and  EG;  F  L  will  be  the  angular 
advance. 

To  equalize  the  cut-off. —  By  inspection  of  Fig.  1,  it  is  evident 
that  if  line  a  6  be  moved  towards  the  centre,  0,  the  arc  b  e  will 
approach  B,  and  cut-off  e,  which  is  earliest,  will  be  made  later 


THE   engineer's  HANDy-BOOK. 


209 


In  like  manner  if  line  c  d  he  moved  farther  from  the  centre,  cut- 
(iff  /  will  be  made  earlier.  These  changes  represent  increased 
lead  at  A  and  diminished  lead  at  B.  In  constructing  a  diagram, 
however,  representing  a  given  equalized  cut-off,  it  will  be  prefer- 
able to  begin  by  locating  the  points  of  cut-off  at  the  desired  part 
of  the  stroke,  say  three-fourths,  as  at  /  e,  Fig.  2,  from  which  points 
draw  the  arcs  e  b  and  /  d.    Then,  as  inspection  of  Fig.  1  has  shown 


z 


b 

G 

A 

hi 

f  m\ 

9 

B 

a 

H 



e 

Fig. 


that  the  lead  at  B  required  diminishing,  the  lead  at  that  end  may 
be  rejected  altogether,  which  will  be  represented  by  drawing  a  line 
from  d  to  B,  Then  a  line  from  h  parallel  to  it  will  cut  the  circle 
at  a,  indicating  that  over  of  an  inch  lead  will  be  required  at 
that  end  (nearest  the  crank  as  before  explained),  against  none  at 
the  other  to  equalize  the  cut-off  at  three-fourths  stroke.  From 
this  it  will  be  seen  that  the  cut-off  can  only  be  equalized  at  the 
expense  of  the  equality  of  the  lead. 
18*      *  O 


210 


THE   engineer's  HANDY-BOOK. 


To  equalize  the  exhaust  at  a  given  part  of  the  stroke.  Sup- 
pose the  desired  point  be  H  inches  from  the  end;  set  off  the 
points  at  h  g,  Fig.  2,  and  draw  arcs,  h  H  and  g  G,  as  before 
directed.  Then  supposing  the  angular  advance,  F  L,  and  with  it 
the  lines,  a  b  and  B  d,  to  have  been  fixed,  draw  HI  and  G  J 
parallel  to  a  6  and  B  d,  and  from  points  /  and  J  draw  arcs  /  i 
and  Jj,  which  will  locate  the  points  of  exhaust-closure  aty  and  i. 
The  distance,  C  K,  will  be  the  exhaust-laps  required  at  the  end 
of  the  valve  next  the  crank,  and  the  distance  of  line,  I from 
centre,  (7,  will  be  the  negative  lap  (^.  e,,  the  amount  less  than  no 
lap)  required  at  the  other  end.  To  determine  whether  the  dis- 
tance of  a  line  indicating  the  exhaust-lap  (as  I  H)  from  the 
centre  indicates  positive  or  negative  lap,  observe  the  effect  of  in- 
creasing its  distance  from  the  centre.  If  the  exhaust  located  by- 
it  at  one  end  should  be  made  earlier,  and  the  exhaust-closure 
located  by  it  at  the  other  end  made  later,  the  lap  indicated  by  it 
is  negative.  Thus,  to  move  J^f  farther  from  (7  would  make  ex- 
haust h  earlier  and  exhaust-closure  i  later;  hence  it  indicates 
negative  lap.  The  reverse  effect  would  follow  by  moving  G  J 
farther  from  the  centre ;  hence  C^is  positive  lap. 

Fig.  3.    To  compromise  between  unequal  lead  and  cut-off. — 
The  lead  inequality  shown  to  be  necessary,  in  order  to  obtain 
equal  cut-off*,  may  be  in  some  cases  so  undesirable  as  to  render 
only  a  partial  equalization  of  the  cut-off*  preferable.    Fig.  3 
shows  such  a  compromise.    It  shows  that  by  giving  \  inch  lead  I 
at  A,  and  none  at  B,  the  cut-off*  will  be  sufficiently  equalized  for  ) 
all  practical  purposes,  as  the  diff*erence  is  reduced  about  one-half  ! 
as  compared  with  Fig.  1.    It  will  also  be  noticed  that  in  Fig.  3 
the  exhaust-lap  has  been  increased  to  -f^  at  C  iT,  and  about  \ 
inch  at  C  m,  both  positive,  which  gives  equalized  exhaust-closure 
at  J  j,  and  very  nearly  equal  exhaust  at  h  g.    The  excess  of  lead 
at  A  over  B  of  course  diminishes  the  lap  C  D,  and  increases  the , 
port  opening,  F  D,  at  that  end.  i 

Fig.  4  shows  the  data  obtained  from  Fig.  3  applied  to  the  con-jl 
struction  of  a  common  slide-valve.    The  scale  of  the  valve  i^jl 


THE    engineer's    II  A  N  I)  Y  -  H  O  O  K  .  211 

made  one-half  size  for  convenience.  The  valve  is  shown  at  mid- 
travel ;  Ck  shows  the  exhaust-lap  obtained  from  Fig.  8  at  Ck 
and  b  m ;  that  at  Cm,  steam-lap;  a  E  is  obtained  from  Fig.  3  at 
C  E;  and  c  D  \n  like  manner  from  C  D.  It  will  be  seen  that, 
notwithstanding  there  is  less  steam-lap  at  D  than  at  £,  the  lap  k 
D  is  slightly  greater  than  Em,  which  is  due  to  the  fact  that  the 
exhaust-lap  added  at  k,  to  equalize  the  exhaust  and  compressioa* 


Fig.  4. 


slightly  more  than  compensates  for  the  lesser  steam-lap  at  D.  If 
the  steam-lap  at  D  had  been  lessened  until  k  D  equalled  E  m,  the 
cut-off  would  have  been  more  nearly  equal  than  is  shown  on  Fig. 
3,  but  still  not  entirely  so.  From  this  it  will  appear  that  valves 
may  be  constructed  (as  they  mostly  are)  with  the  two  laps  equal 
in  width,  and  in  setting  them,  the  exhaust  and  compression  may 
be  equalized,  letting  the  cut-off  equalization  take  care  of  itself, 
which  it  will  do  by  becoming  a  trifle  more  than  half  equalized, 
as  compared  with  Fig.  1.  Such  a  valve,  considered  apart  from  the 
seat  on  which  it  works,  would  appear  to  have  equal  laps  of  both 
kinds,  and  might  be  so  set,  as  is  the  case  in  the  adjustment  repre- 
sented by  Fig.  1 ;  but,  when  set  to  equalize  the  compression  and 
exhaust,  it  must  be  considered  as  having  unequal  laps  of  both 


212  THE  engineer's  hanby-book. 


kinds.  A  valve  constructed  from  the  dimensions  furnished  by 
Fig.  2,  in  which,  as  we  have  seen,  the  cut-off,  exhaust,  and  com- 
pression were  entirely  equalized  at  the  expense  of  lead,  equality 
would  have  the  lap  k  D  the  shortest. 

In  determining  the  best  point  for  exhaust-closure,  it  should  be 
borne  in  mind  that  this  event  is  the  one  which  stands  most  in  the 
way  of  an  early  cut-off,  and  that  it  is  desirable  to  know  how  early 
it  may  be  located,  without  detriment  to  the  performance  of  the 
engine.  The  decision  of  this  point  will  depend  mainly  on  the 
amount  of  clearance  present.  If  the  clearance  is  great,  consider- 
able compression  is  not  only  admissible,  but  desirable;  as  the 
greater  the  clearance  the  less  the  loss  of  mean  effective  pressure 
by  the  counter-pressure  resulting  from  early  exhaust-closure.  The 
steam  shut  in  by  the  closure  of  the  exhaust  is  saved,  to  be  used 
over  again  during  the  next  stroke ;  and,  when  the  clearance  is 
great,  the  loss  of  power  by  early  compression  is  more  than  com- 
pensated by  the  saving  of  steam ;  the  result  is^a  certain  amount 
of  net  gain  in  economy.  As  a  general  rule,  the  maximum  com- 
pression pressure  should  not  exceed  the  pressure  present  in  the 
steam-chest.  If  it  should,  the  valve  is  liable  to  be  forced  from 
its  seat;  and  not  only  so,  but  the  limits  within  which  compression 
improves  the  economy  would  be  exceeded. 

When  the  clearance  is  known,  and  is  reduced  to  a  certain  per- 
centage of  the  stroke,  the  compression  may  be  fixed  at  three  to 
five  times  the  clearance,  which  would,  theoretically,  raise  the  com- 
pression pressure  to  from  three  to  five  atmospheres ;  but,  in  prac- 
tice, the  theoretical  maximum  is  seldom  reached.  Thus,  suppose 
the  clearance  of  an  engine  to  be  equal  to  its  displacement  during 
one  inch  of  its  stroke,  and  the  valve  to  close  the  exhaust  four 
inches  from  the  end  of  the  stroke ;  or,  in  other  words,  suppose  the 
compression  to  be  four  times  the  clearance,  the  maximum  compres- 
sion pressure  should,  theoretically,  reach  55  to  50  lbs. ;  but  it  will 
seldom,  in  practice,  exceed  50  lbs.,  unless  the  cylinder  is  jacketed 
with  live-steam,  and  the  valve  and  piston  are  very  tight. 

The  proper  point  to  release  the  steam  will  depend  upon  thQ 


THE   engineer's  HANDY-BOOK. 


213 


travel  of  the  valve,  the  capacity  of  the  cylinder-ports,  and  the 
exhaust-passage  in  the  valve.  If  these  are  ample,  the  release  may 
occur  later  than  when  they  are  not.  The  point  to  be  aimed  at  in 
locating  it,  is  to  release  in  time  to  avoid  any  considerable  back 
pressure  at  the  beginning  of  the  return  stroke.  No  responsible 
engine-builder  of  the  present  day  will  fix  on  a  valve  construction 
and  adjustment  permanently,  until  he  has  first  tested  its  results 
Viith  the  indicator,  and  satisfied  himself  that  they  are  the  beat 
possible  with  the  slide-valve. 


The  above  cut  represents  the  Myers  slide-valve.  G  C  shows 
the  main  valve,  which  is  whole  stroke ;  D  D  shows  the  cut-ofF, 
what  is  termed  the  riding  cut-oflf,  because  it  rides  on  the  back  of 
the  main  valve,  and,  as  will  be  observed,  the  amount  of  expansion 
is  regulated  by  right  and  left  hand  screws  passing  through  the 
cut-oflT  valves,  and  shown  above,  D  D.  By  turning  the  hand- 
wheel,  L,  to  the  right,  the  cut-oflT  will  be  decreased,  while  by  turn- 
ing to  the  left  it  will  be  increased.  H  H  shows  the  steam-ports  ; 
Q,  the  exhaust  cavity,  and  F,  the  exhaust  opening  in  the  valve- 
face;  J  J,  the  valve-stems  passing  through  guides  on  the  back  end 
of  the  stuflSng-box  ;  K  K  shows  the  bonnet  of  the  steam-chest : 
and  M,  the  spindle  which  carries  the  right  and  left  screws.  I  is 
the  main  valve-stem  ;  iV,  a  bracket  for  the  purpose  of  holding  the 
quadrant,  0,  in  position,  and  preventing  the  cut-oflT  from  varying 
when  it  is  once  set.  This  description  of  valve  is  used  on  nearly 
all  large  ocean  steamers. 


214 


THE   ENGINEER'S  HANBY-BOOK. 


The  Wheelock  Automatic  Cut-Off  Engine. 

The  cut  on  page  215  shows  the  cylinder,  valve-gear,  gov- 
ernor, and  part  of  the  housing  of  the  "  Wheelock  Automatic  Cut- 
OfT  Engine,"  and  that  on  page  216  a  section  of  the  same.  In 
general  appearance,  the  Wheelock  engine  bears  a  close  resem- 
blance to  the  Corliss  type,  except  that  the  absence  of  the  cut-off 
valves  at  the  top  of  the  cylinder  removes  the  necessity  for  the 
square  corners,  and  that  the  guides,  though  like  those  of  the  Cor- 
liss, are  parallel  with  the  plane  of  vibration  of  the  connecting- 
rod,  and,  in  place  of  being  V-shaped,  are  curves  bored  out  on  a 
line  with  the  axis  .of  the  cylinder.  This  insures  pei^fect  accuracy, 
and  prevents  the  possibility  of  the  piston  and  cross-head  getting 
out  of  line. 

The  valves  receive  their  motion  from  an  ordinary  eccentric,  and 
perform  the  double  function  of  admitting  and  cutting  off  steam. 
Their  seats  are  as  close  to  the  bore  of  the  cylinder  as  is  consistent 
with  a  proper  allowance  of  material,  thus  reducing  the  clearance 
to  a  minimum.  The  valve-motion  is  very  ingenious,  effective,  and 
simple.  The  cut-off  is  effected  by  tripping  the  valves  with  an  ar- 
rangement which  dispenses  with  the  necessity  of  dash-pots,  weights, 
or  levers,  as  by  means  of  lugs  on  the  lifters  coming  in  contact 
with  the  spring  catches,  which  engage  rock-arms  on  the  valves, 
the  same  effect  is  produced.  The  governor  is  of  a  design  pecu- 
liarly adapted  to  these  engines,  and,  in  consequence  of  its  sensi- 
tiveness, holds  the  valve-gear  under  complete  control,  and  insures 
a  steady  motion  of  the  engine  under  the  most  varying  circum- 
stances of  load  and  pressure. 

The  Wheelock  engines  are  in  very  general  use  in  the  East- 
ern States,  and  seem  to  give  satisfaction.  One  of  them  which 
was  running  in  the  Agricultural  Department  of  the  Centennial 
Exhibition,  held  at  Philadelphia  in  1876,  attracted  a  good  deal 
of  attention,  on  account  of  its  smooth  and  noiseless  working.  The 
most  objectionable  feature  of  these  engines  is  the  liability  of  the 
valves  to  become  leaky. 


THE  engineer's  HANDY-BOOK. 


217 


Lap  on  the  valve.  —  The  term  lap  on  the  valve  denotes  the 
amount  the  edges  of  the  valve  extend  over  the  ports  when  tke 
valve  is  in  the  centre  of  its  travel.  If  a  valve  has  |  lap,  it  is 
understood  to  extend  I  beyond  the  ports  when  placed  centrally 
over  them.  The  object  of  lap  is  to  secure  the  benefit  to  be  derived 
from  working  steam  expansively.  Lap  on  the  steam  side  is  termed 
outside  lap,  while  lap  on  the  exhaust  side  is  termed  inside  lap. 

Poppet-  or  conical-valves  cannot  have  any  lap;  but  the  sama 
effect  is  produced,  as  in  the  case  of  the  slide-valve,  by  arranging 
the  cams  and  lifting-toes  so  that  the  valve  may  close  at  the  proper 
time  to  give  the  necessary  degree  of  expansion.  The  lift  of  poppet- 
valves,  to  give  an  opening  equal  to  the  area  of  the  port,  is  ^  the 
radius  or  |  the  diameter. 

Lead  on  the  valve.  — The  (^bject  of  lead  is  to  enable  the  steam 
to  act  as  a  cushion  against  the  piston  before  it  arrives  at  the  end 
of  the  stroke,  to  cause  it  to  reverse  its  motion  easily,  and  also 
to  supply  steam  of  full  pressure  to  the  piston  the  instant  it  has 
passed  dead-centre.  It  varies  in  different  engines  from  to  /g, 
without  regard  to  size  or  kind.  It  often,  however,  exceeds 
but  perhaps  very  seldom ;  while  some  valves  have  no  lead  at  all, 
others  less  than  none,  or  what  is  termed  "  negative  lead.''  The 
higher  the  speed  and  the  more  irregular  the  work  the  more  lead 
will  be  required  for  any  engine. 

Loss  of  lead  is  a  term  employed  to  express  the  inequalities  of 
the  lead  at  one  end  of  the  cylinder  induced  by  the  expansion  of 
valve-rod.  It  may  occur,  however,  at  both  ends,  through  lost 
motion  in  the  joints  or  displacement  of  the  eccentric. 

Lead  on  the  steam  end  is  a  term  applied  to  the  amount  of 
opening  the  valve  has  at  the  end  of  the  cylinder  into  which  the 
steam  is  entering.  Lead  on  the  exhaust  end  means  the  amount 
of  opening  the  valve  has  on  the  end  from  which  steam  is  escaping. 
The  name  applies  alternately  to  each  end  of  the  cylinder. 

Line  and  Line. — A  term  applied  to  slide-valves  when  thev 
have  no  exhaust  lead,  as  shown  in  Fig.  3,  on  page  204. 
19 


218 


THE   engineer's  HANDY-BOOK, 


Valve-seat. — The  flat  surface  which  contains  the  ports,  and  on 
which  the  valve  moves. 

The  valve-face  is  the  working  surface  of  the  valve  which  moves 
on  the  valve-seat. 

Valve-circle.  —  The  term  valve-circle,  though  sometimes  used, 
is  inappropriate,  as  a  valve  does  not  describe  a  circle.  It  means 
a  circle  which  would  have  a  circumference  equal  to  the  distance 
•travelled  by  the  valve  in  two  strokes  or  one  revolution.  Such  a 
circle  would  be  smaller  than  that  described  by  the  centre  of  the 
eccentric,  unless,  as  is  sometimes  the  case,  the  rocker-arms  were 
so  arranged  as  to  give  a  greater  travel  to  the  valve  than  to  the 
eccentric. 

Valve-stroke.  —  The  travel  or  stroke  of  a  slide-valve  is  the  dis- 
tance it  moves  on  its  face  to  give  the  proper  opening  of  the  port. 


How  to  Determine  the  Amount  of  Lap  and  lead  on  a  Yalve 
without  Opening  the  Steam-Chest,  and  whether  it  is  Equal 
at  both  Ends  or  not. 

Open  the  cylinder  drain-cocks  and  disconnect  them  from  the 
drip-pipes,  so  that  the  steam  may  be  seen  and  heard  to  issue  from 
them.  A  better  plan  is,  to  open  the  holes  made  for  the  indicator, 
if  there  are  any;  at  all  events,  open  as  large  holes  as  possible ;  then 
let  in  a  very  little  steam,  turn  the  engine  around  by  hand,  and 
note,  by  the  commencement  and  cessation  of  the  flow  of  steam, 
just  where  the  steam  is  admitted  and  cut-ofi*.  The  point  of  cut- 
off* can  be  most  accurately  ascertained  by  turning  the  engine 
backwards ;  the  steam  will  in  this  case  commence  blowing  at  the 
same  point  in  the  stroke  at  which  it  would  cease  blowing  when 
turning  it  forward ;  and,  owing  to  the  elasticity  of  steam,  the 
commencement  of  the  issue  is  always  more  clearly  defined  than 
the  cessation,  particularly  when  the  issuing  orifice  is  small.  For 
the  same  reason,  the  point  of  admission  can  be  most  accurately 
located  by  turning  the  engine  forward. 


THE   ENGINEEK^S    HANDY-BOOK.  219 

To  determine  the  lead,  having  found  the  point  of  admission, 
ifiake  a  mark  on  the  valve-stem  at  a  known  distance  from  some 
fixed  point,  and  another  after  the  pin  has  reached  the  centre  ;  this 
will  give  the  lead.  If  the  admission  forw^ard  takes  place  when  the 
crank-pin  is  exactly  on  the  dead-centre,  there  is  no  lead.  Having 
obtained  the  lead  and  cut-off  for  both  ends,  the  travel  and  length 
of  the  connection  being  known,  a  diagram  may  be  constructed 
similar  to  Figs.  1,  2,  and  3,*which  will  give  the  lap  and  port-open- 
ing. 

The  point  of  exhaust  and  compression  cannot  be  determined  so 
readily.  With  a  small  engine,  in  which  the  piston  and  valve  are 
steam-tight,  the  points  may  be  ascertained  by  blowing  into  the 
cylinder  through  pipes  attached  to  the  cylinder-cocks  or  the  holes 
for  indicator,  if  any.  The  exhaust  would  be  indicated  by  the 
point  where  the  air  would  begin  to  pass  through  into  the  exhaust, 
and  the  closure,  by  noting  the  point  where  it  ceased  to  pass 
through. 

But  in  engines  of  any  size,  especially  leaky  ones,  the  plan  of 
blowing  in  with  the  mouth  would  be  inapplicable.  With  non- 
condensing  engines,  however,  much  may  be  learned  by  listening 
to  the  exhaust ;  if  the  puffs  occur  at  equal  intervals,  and  are  of 
equal  force,  good  equalization  may  be  inferred ;  and,  if  they  are 
short,  quick,  and  free,  and  are  followed  by  a  free  and  nearly  noise- 
less escape  of  the  residuary  steam,  the  exhaust  is  early  and  ample 
enough.  On  the  other  hand,  too  late  an  exhaust  will  produce 
more  prolonged  and  labored  puffs.  It  is  needless,  however,  to 
remind  the  reader  that  nothing  can  take  the  place  of  the  indicator 
for  determining  all  the  conditions  and  adjustments  of  the  valve, 
particularly  its  exhaust  and  compression,  as,  even  when  the  nicest 
measurements  and  calculations  are  resorted  to,  doubts  may  still 
exist  as  to  the  truthful  movements  of  the  valve,  which  nothing 
but  an  application  of  the  indicator  can  satisfactorily  remove. 


220  THE  engineer's  handy-book. 


TABLE 

SHOWING  THE  AMOUNT  OF  "  LAP  "  REQUIRED  FOR  SLIDE-VALVES  WHEN 
THE  STEAM  IS  TO  BE  WORKED  EXPANSIVELY. 


When  the  travel  of  the  valve  is  known,  and  the  point  of  cut- 
off decided,  the  following  table  will  show  the  amount  of  lap  re- 
quired.* 


Travel 
of  the 
Valve 

in 
Inches. 

The  Travel  of  the  Piston  when  the  Steam  is  cut  off 

I 

4 

1 

3 

5 

T3 

1 

7 

2 
3 

3 
"4 

1 0 

jjj 

The  required  "  Lap." 

.  2 

3 

3| 
4 

4^ 

5 

5^ 
6 

6| 
7 

7i- 
8 

8i 
9 

10 
11 
12 

i 

U 

1-2 

i| 
2 

2| 

2A- 
2i 

2| 
3 

3A 

Q  5 
^  ff 
Ql  3 

4 

41 

4tV 

4A 

41  3 
5 

3 
4 

1 

1  6 

2 

9  9 
91  1 

3 

4 

4-7- 

4_9_ 
^1  6 
41  3 

1  1 

T6 
7 
8" 

u 

1  7 

^  1  6 
1  1  3 

2 

9  3 

9  » 

3H 

4 

41 
4tV 

4T«g 

5 
8" 
1  3 
T6 

1 

H 

U 

1  9 
^  1  6 

2 

9  3 

21 
2i 

9  5 

3 

3A 

3A 
3i 

^  8 
Q  7 

4  J- 

^  8 

1 1 

T5 
1  5 

Te 
ItV 
li 
If 

If 

HI 
2 

2A 
2| 
2|- 

91  1 
91  3 

3/5 

3fV 
3i 

3| 
4 

1 

3 
4 

1 

ItV 

U 

1| 

If 

1  1  3 

2 

9  3 
^3 -J 

2| 

2i 
91 1 

^Tg 
91  3 

3 

3| 
3iV 
3| 
3f 

■ 

7 

Tg 

3 
5 
IS' 

i 

1 

u 
If 

U 
If 
1| 

2 

2i 

21 

2| 

2-^ 

2f 

2| 
9  7 

3 

3 

8 

tV 

9 

3 
4 

H 

-'^  ¥ 
1  3 

1  1 
^  4 

1  1 

1  3 
^  4 

2  1 

2/6 

21 
2| 
2^ 

It  is  not  advisable  to  cut  off  earlier  with  a  single  slide-valve 


^  If  a  valve  has  J  lap,  it  will  overlap  each  steam-port  |  of  an  inch  when 
placed  centrally  over  them. 


THE   engineer's  HANJ)Y-H00K. 


221 


than  at  ^  or  |  stroke,  as  otherwise  the  lap  would  be  excessive 
and  the  freedom  of  the  exhaust  impaired.  lu  locomotives  and 
marine  engines  the  case  is  different,  as  the  cut-off  may  be  effected 
at  almost  any  point  through  the  agency  of  the  link. 

Rule  for  finding  the  point  of  cut-off  required  to  produce  a  given 
terminal  from  a  given  initial  pressure. 

Divide  the  total  terminal  by  the  total  initial  pressure.  The 
quotient  will  be  the  point  of  cut-off  in  decimal  parts  of  the  stroke. 

Example. — Initial  pressure,  20  lbs.  per  sq.  in.  Terminal,  13  lbs., 
measured  from  a  vacuum.  Then  13  lbs.  20  =  '65  of  the  stroke ; 
or  divide  the  volume  of  the  initial  by  that  of  the  terminal,  the 
quotient  will  be  the  point  of  cut-off  in  decimal  parts  of  the  stroke. 

Example  —  Vol.*  of  20  =  1229.  Vol.  of  13  =  1842.  Then 
1229  -T- 1842  =  -667  of  the  stroke. 

Rule  for  finding  the  point  of  cut-off  when  the  initial  and  mean 
pressure  are  known. 

Add  the  pressure  of  the  atmosphere  to  the  initial  and  mean 
pressures,  and  divide  the  mean  pressure  by  the  initial.  Then  find 
in  the  table  of  multipliers,  page  69,  the  number  nearest  the  quo- 
tient. Find  the  number  opposite  to  it  in  the  expansion  column, 
find  divide  100  by  it;  the  quotient  will  be  the  point  of  cut-off  in 
decimal  parts  of  the  stroke. 

Exampl^. — Stroke  of  piston,  10  ft.  Initial  pressure,  10  lbs.  per 
fiq.  in.  Mean  pressure,  8  lbs.  Mean  effective  pressure,  atmos- 
phere added,  22*50.  Initial  pressure,  atmosphere  added,  24*5. 
Quotient  of  first  divided  by  last,  '918.  Expansion  number  in  table 
opposite,'919,  which  is  nearest  number  to  above  quotient,  1*6;  100  -r- 
1-6  =  -625  or  1^  of  the  stroke.  Either  of  the  foregoing  rules  will 
make  the  cut-off  take  place  a  trifle  earlier  than  it  would  in  practice. 

Friction  of  Slide -Valves. 

Many  estimates  have  been  made  concerning  the  power  absorbed 
in  overcoming  the  friction  of  slide-valves,  and  probably  on  no  sub- 
ject has  there  been  a  greater  diversity  of  opinion.    It  has  been 
*  See  Table  of  Volumes,  pages  76  to  87. 

19* 


222  THE  engineer's  handy-book. 

assumed,  on  the  one  hand,  that  as  much  as  one-fourth  of  the  power 
of  an  engine  is  wasted,  while  others  claim  that  the  loss  of  power 
is  merely  nominal.  An  idea  has  been  very  generally  entertained 
by  engineers  that  the  number  of  square  inches  in  a  slide-valve, 
and  the  pressure  of  steam  in  pounds  per  square  inch,  represented 
the  total  pressure  on  its  back ;  or,  in  other  words,  that  the  press- 
ure was  equal  to  the  pressure  of  steam  per  square  inch  on  the 
back  of  a  valve,  minus  the  area  of  the  steam-ports. 

Such  conclusions  are  erroneous,  however,  as  the  number  of 
square  inches  in  a  slide-valve,  and  the  pounds  pressure  per  square 
inch,  represent  only  the  weight  on  its  back,  if  we  consider  the 
valve  as  a  solid  block  of  iron,  with  a  smooth  surface  resting  on  a 
smooth,  solid  bearing,  perfectly  steam-tight,  in  which  case  the 
steam  would  press  on  every  square  inch  of  surface  with  the  same 
force  as  a  dead  weight.  There  is  good  reason  to  believe  that 
such  conditions  are  never  found  in  a  slide-valve,  except  in  one 
position,  viz.,  when  the  valve  overlaps  both  ports  and  the  engine 
is  at  rest.  As  soon,  however,  as  the  valve  moves,  the  steam  enters 
the  open  port,  and  the  pressure  is  partially  taken  off  thai  end  of  it. 

Rule  for  finding  the  pressure  on  slide-valves. 

Multiply  the  unbalanced  area  of  the  valve  in  inches  by  the 
pressure  of  steam  in  pounds  per  square  inch ;  add  the  weight  of 
the  valve  in  pounds,  and  multiply  the  sum  by  0*15.  ^ 

Another  pule. —  Multiply  the  combined  area  of  the  bearing  sur- 
face and  ports  in  inches  by  the  steam  pressure  in  pounds  per 
square  inch  on  the  back  of  the  valve;  multiply  this  product  by 
the  coefficient  of  friction  between  the  two  surfaces.  The  product 
will  be  the  force  required  to  move  the  valve  when  unbalanced. 

The  better  the  slide-valve  is  fitted,  the  more  power  it  takes  to 
work  it;  and  a  valve  that  is  perfectly  steam-tight  on  its  seat, 
takes  immensely  more  power  to  move  it  than  if  poorly  fitted; 
because,  if  a  valve  is  leaky,  there  is  always  a  film  of  steam  be- 
tween the  valve-face  and  the  seat ;  but,  when  the  valve  is  perfectly 
steam-tight,  there  is  nothing  to  lessen  the  friction  except  the  lu- 
brication. 


THE   engineer's   HANDY-BOOK.  223 


The  above  cut  represents  poppet,*  or  double-beat,  valves,  such 
as  are  used  in  connection  with  the  Stevens'  Cut-OfF,  or  what  is 
termed  the  Stevens'  Front.  It  will  be  observed  that  the  valves 
on  the  left  side  are  open  for  the  admission  of  steam,  while  those 
on  the  right  are  closed.  The  lift  of  such  valves,  if  single,  would 
be  about  |  of  their  diameter ;  but  when  they  are  double,  as  in 
the  present  case,  ^  lift  would  give  an  area  equal  to  the  opening  of 
the  steam-port.  One  of  the  greatest  difficulties  experienced  in  the 
working  of  such  valves  is,  that,  however  carefully  they  may  be 
fitted,  their  stems  will  expand  and  induce  leakage  in  the  valves 
when  exposed  to  a  high  temperature.  For  this  latter  difficulty 
there  appears  to  be  no  remedy. 

Nevertheless  such  valves  have  their  advantages,  among  which 
are,  that  they  can  be  turned  up,  or  ground  on  to  their  seats  at  a 
moderate  cost,  since  the  process  of  their  manufacture  is  all  lathe 
work ;  that  in  their  working,  there  is  no  power  absorbed  by  fric- 
tion, as  in  the  case  of  the  slide-valve,  and  that  they  can  be  placed 

*  Puppet  is  the  correct  word,  though  poppet  is  most  generally  adopted  by 
engineers. 


224 


THE   engineer's  HANDY-BOOK. 


SO  near  the  cylinder  as  to  reduce  the  clearance  to  a  minimum. 
Such  valves,  however,  would  not  answer  for  high-speed  engines, 
as  at  high-piston  velocity,  and  considerable  back  pressure,  they 
would  not  seat. 

How  to  Set  the  Yalves  of  Steam-Engines. 

No  definite  instructions  that  would  apply  to  all  cases  can  be 
given  for  setting  the  valves  of  steam-engines.  As  the  circum- 
stances under  which  the  engines  and  valves  are  employed  must, 
to  a  certain  extent,  influence  and  control  this  operation,  fast-run- 
ning engines  require  more  lead  than  those  that  run  slowly.  En- 
gines doing  heavy  and  irregular  work  also  require  more  lead  than 
those  working  with  a  uniform  load.  Some  engines  require  no  lead 
at  all,  while  others  require  a  great  deal. 

The  valves  of  a  steam-engine  may  be  adjusted  with  great  ac- 
curacy by  an  intelligent  and  practical  engineer,  providing  that 
all  the  valve-gear  is  of  correct  proportions ;  but  there  are  diffi- 
culties to  be  contended  with  which  frustrate  the  efforts  of  the  most 
practical  mechanics,  and  must  ever  do  so,  unless  we  discover  a 
new  material  for  valves  and  valve-gear.  Valves  may  be  set  with 
the  nicest  mechanical  accuracy,  opening  and  closing  the  ports  with 
precision  when  the  valves  and  valve-gear  are  cold ;  but  when  ex- 
posed to  high  temperatures  they  may  be  far  from  accurate  in 
their  travel.  All  metals  expand  with  heat  and  contract  with  cold, 
and  a  valve  that  will  give  uniform  lead  at  each  end  of  the  stroke 
when  cold,  will  not,  in  all  probability,  do  so  when  exposed  to  the 
action  of  the  steam,  as  the  valve  and  valve-rod  will  expand,  pro- 
duce a  loss  of  lead,  increase  the  amount  of  lap,  and  alter  the  con- 
ditions under  which  the  engine  was  intended  to  work. 

This  change  is  not  confined  to  slide-valve  engines,  as  the  stems 
of  poppet-valves  are  lengthened  by  expansion,  decreasing  the  lift 
and  also  the  lead,  and  inducing  a  very  different  condition  of  things 
from  what  would  exist  if  the  valves  could  be  used  at  the  tempera- 
ture at  which  they  were  adjusted.  Thousands  of  indicator  dia- 
grams show  conclusively  that  the  behavior  of  valves,  when  exposed 


T  II  E    K  N  G  I  N  K  p:  It  \s    HANDY-  H  O  O  K  . 


225 


to  high  temperature,  is  very  different  from  what  they  are  when 
cold.  One  of  the  best  aids  to  correct  valve-setting  is  a  good  indi- 
cator, as  nothing  shows  the  action  of  the  steam  in  the  cylinder  so 
<5orrectly  as  this  instrument.  It  tells  exactly  when  the  steam  goes 
in  and  out  of  a  cylinder,  because  it  maps  down  the  motions  of  the 
steam  as  determined  by  the  motions  of  the  valve  and  piston,  re- 
cording faithfully  the  times  and  pressures  as  they  actually  are. 

To  set  a  slide-valve,  place  the  crank  on  the  dead-centre  and 
the  valve  centrally  on  its  seat  over  the  ports;  then  adjust  the 
valve-gear  to  the  right  length,  and  move  the  eccentric  round  in 
the  direction  in  which  the  engine  is  intended  to  run,  until  the 
proper  lead  is  attained,  as  shown  in  Fig.  1,  page  204 ;  then  turn  the 
engine  on  the  opposite  centre,  and,  if  the  lead  is  exactly  the  same, 
the  valve  ought  to  travel  equally  on  its  seat,  and  the  exhaust 
appear,  as  in  Fig.  2,  page  204.  Any  difference  in  the  lead  at 
either  end  must  be  equalized  by  lengthening  or  shortening  the 
valve-gear,  as  the  case  may  be. 

An  intelligent  engineer  can  generally  tell  by  observation  whether 
engines  exhaust  regularly  or  not ;  as,  if  the  steam  is  discharged 
with  long  or  short  puffs,  alternately,  or  shows  what  is  technically 
termed  a  long  and  short  leg,  it  is  evident  that  the  valve  has  an 
earlier  and  a  freer  exhaust  at  one  end  than  at  the  other ;  never- 
theless, one  exhaust  may  be  heavier  than  the  other,  and  yet  the 
intervals  between  them  may  be  equal.  In  such  cases  the  exhaust 
is  equal  as  to  time,  but  not  as  to  amount.  The  difference  in 
amount  may  be  caused  by  unequal  degrees  of  expansion,  and  this 
in  turn  may  be  caused  by  unequal  cut-off,  or  unequal  clearance, 
or  both.  Such  inequality  cannot  be  cured  by  mere  adjustment, 
since  the  lap  requires  to  be  changed ;  but  in  most  cases  an  im- 
provement may  be  effected  by  a  compromise  between  equalized 
cut-off  and  exhaust,  so  tliat  the  effects  of  the  inequality  of  both 
would  not  be  noticeable. 
I  In  the  case  of  fast-running  engines,  or  where  the  exhaust  has 
to  pass  through  long  pipes,  this  inequality  is  not  easily  determined 
from  the  appearance  of  the  exhaust ;  but  it  may  be  done  more 

P 


226 


THE    engineer's  HANDY-BOOK. 


accurately  by  holding  the  ear  close  to  the  exhaust-pipe.  This 
latter  method  may  also  be  resorted  to  in  the  case  of  low-pressure 
engines  exhausting  into  a  condenser. 

Valves  and  Valve-Gear. 

The  term  valve-geap'embraces  all  intermediate  connections  be- 
tween the  eccentric  on  the  driving-shaft  and  the  valves,  and  is 
applicable  to  all  mechanical  arrangements  employed  for  working 
the  valves  of  steam-engines. 

The  valves  most  generally  employed  for  the  admission  of  steam 
to  the  cylinders  of  steam-engines,  are  the  slide,  poppet,  Corliss  or 
semirotary,  and  rotary  ;  plug-  or  piston-valves  are  also  used,  but 
most  generally  for  steam-pumps.  All  valves,  whether  used  for 
the  admission  or  escape  of  steam  to  or  from  the  cylinders  of  steam- 
engines,  receive  their  motion  from  cams,  eccentrics,  or  cranks ;  the 
movements  of  the  former  being  indefinite  as  to  character,  and  of 
the  two  latter,  definite.  Whatever  the  device  employed  to  give 
motion  to  the  valves  may  be  termed,  whether  cams,  eccentrics, 
cranks,  gearing,  rockers,  wrist-plates,  toes,  lifters,  trips,  links,  rods, 
levers,  etc.,  they  may  be  placed  under  the  head  of  valve-gear. 

There  are  engines  without  valves,  such  as  the  Wardwell,  which 
was  on  exhibition  at  the  Centennial  Exposition  at  Philadelphia, 
and  some  kinds  of  oscillating  engines,  in  which  faces  on  the  cyl- 
inder fit  against  faces  on  stationary  steam-chests,  through  which 
the  steam  enters  and  escapes  from  the  cylinder.  Such  arrange- 
ments may  be  called  stationary  valves,  but  they  possess  inherent 
defects,  which  render  them  useless  for  the  most  important  purposes 
for  which  the  steam-engine  is  employed. 

A  releasing  "  valve-gear  is  an  arrangement  in  which  the  valve 
is  liberated  from  the  control  of  its  moving  agent,  and  allowed  to 
close  in  obedience  to  the  action  of  a  spring,  weight,  or  other  force 
independent  of  that  which  opened  it.  The  agent  which  deter- 
mines the  time  of  release  may  be  the  governor,  or  it  may  be,  and 
often  is,  some  device  adjustable  by  hand. 


THE   ENaiNEER\s    HANDY-BOOK.  227 

An  automatic  cut-ofT  valve-gear  is  one  in  which  the  movement 
of  the  cut-ofF  valve  is  so  controlled  by  the  governor,  as  to  cut  off 
the  steam  as  early  or  as  late  in  the  stroke  as  may  he  required,  to 
maintain  the  desired  uniformity  of  speed,  under  variations  of  load 
and  pressure. 

A  positive  cut-off  is  an  arrangement  of  valve-gear  by  which 
the  expansion  of  the  steam  is  effected  by  what  is  known  as  lap  on 
the  valve,  the  steam  being  cut  off  at  the  same  point  in  each  stroke, 
independent  of  load  or  pressure. 

An  adjustable  "  cut-off  is  an  arrangement  of  valve-gear,  m 
which  the  point  of  cut-off  can  be  adjusted  by  the  hand  of  the  en* 
gineer,  outside  of  the  steam-chest,  by  means  of  a  screw,  hand-wheel, 
or  other  mechanical  arrangement,  to  meet  the  requirements  of 
work  and  pressure.  The  link,  in  its  application  to  the  steam-en- 
gine, belongs  to  this  class  of  cut-offs,  as  it  effects  the  adjustment 
of  the  cut-off  by  means  of  coincident  variations  in  the  travel  and 
angular  advance  using  a  single  valve. 

Riding  cut-oflT, —  A  term  applied  to  cut-off  valves  which  ride 
on  the  back  of  the  main  steam-valve. 

An  independent  cut-off  is  one  in  which  the  expansion  is  effected 
by  an  independent  or  auxiliary  valve  riding  on  the  back  of  the 
main  valve,  and  receiving  its  motion  from  an  independent  eccui- 
tric. 

An  expansion  "  valve-gear  is  one  that  cuts  off  the  supply  of 
steam  at  any  required  point  of  the  stroke.  It  embraces  all  the 
foregoing  arrangements. 

A  "whole  "  stroke  valve-gear  is  one  that  admits  steam  through 
the  whole  length  of  the  stroke. 

A  "  reversing  "  valve-gear  is  an  arrangement  employed  for  re- 
versing the  motion  of  engines.  It  is  effected  in  different  ways  :  in 
some  cases  with  a  single  eccentric,  \vhile  in  others  with  two  ec- 
centrics, as  in  the  case  of  the  link ;  and  in  others,  still,  by  means 
of  a  loose  eccentric  which  revolves  on  the  shaft,  but  is  prevented 
from  making  a  complete  revohition  by  tw^o  stops  eo  phiced  that 
one  arrests  it  in  the  proper  position  for  the  forward,  and  the  othe^ 


228  THE  engineer's  handy-book. 

« 

for  the  backward  motion.  This  arrangement  is  peculiarly  adapted 
to  tug-boats  and  ferries,  owing  to  the  ease  and  quickness  with  which 
the  engine  can  be  reversed. 

Double-beat  valves  are  poppet-valves  so  arranged,  that  the 
pressure  of  steam  is  nearly  equal  on  both  sides,  thus  rendering  the 
motion  of  the  valve  much  easier  than  in  the  case  of  an  ordinary 
single-beat  valve.    (See  cut,  page  223.) 

Throttle-valves  are  valves  located  in  the  steam-pipe,  through 
which  steam  is  admitted  to  the  steam-chest.  At  present  their  use 
is  confined  to  locomotives  and  old-fashioned  stationary  engines. 

Relief-valves  are  used  on  the  cylinders  of  large  engines,  par- 
ticularly marine,  to  prevent  fracture  of  the  cylinder-head  and 
cylinder,  in  consequence  of  an  accumulation  of  water  in  the  latter. 
When  a  greater  pressure  is  exerted  in  the  cylinder  than  would 
result  from  the  ordinary  pressure  of  the  steam,  the  relief-valve 
will  open  and  admit  of  the  discharge  of  the  water,  thus  averting 
an  accident.  They  are  used  on  fire-engines  for  the  purpose  of 
preventing  the  hose  from  bursting  when  the  escape  of  the  water 
is  obstructed. 

Balance-valves. — Arrangements  by  which  the  weight  on  the 
back  of  slide-valves,  induced  by  the  pressure  of  the  steam,  is  re- 
lieved by  the  action  of  the  steam  in  the  steam-chest. 

Rotary-valves. — A  term  applied  to  any  valve  that  describes  a 
revolution  in  working. 

Semirotary- valves.— A  term  applied  to  all  valves  similar  to 
the  Corliss  that  have  a  vibratory  or  rocking  motion. 

Starting -valve  gear. — A  mechanical  arrangement  employed  in 
connection  with  a  small  engine,  called  the  starting-engine,  for 
moving  the  valves  of  large  engines  when  stopping  or  starting. 

Gridiron-valves. — A  modification  of  the  slide-valve,  containing 
a  number  of  openings  for  the  steam,  by  which  means  its  travel 
and  friction  are  materially  diminished. 

Dash-pot. — An  arrangement  employed  for  closing  the  valves 
of  engines  of  the<Jorliss  type,  and  in  many  instances  for  arresting 
the  closing  movement  when  it  is  sudden  and  violent.    The  dash- 


THE   engineer's  HANDY-KOOK. 


229 


pots  contain  usually  either  water  or  oil,  though  in  many  instances 
they  are  cushioned  with  air. 

Spring-levers.  —  Arrangements  employed  for  closing  semiro- 
tary-  and  poppet-valves.  They  are  a  substitute  for  the  dash-pot, 
which  has  many  advantages  over  them,  on  account  of  the  dis- 
agreeable noise  induced  by  their  workings. 

Lifters. — A  term  applied  to  the  toes  on  the  lifting-rods,  which 
open  and  close  the  valves  of  steam-engines,  particularly  those 
constructed  with  what  is  called  a  Stevens'  front. 

Wrist-plate. — An  arrangement  employed  in  engines  of  the  Cor- 
liss type  for  transmitting  the  motion  of  the  eccentric  to  the  valves, 
and  in  many  instances  for  modifying  their  throw  or  movement.. 

Trips. — A  term  applied  to  the  pawls  which  liberate  the  valves 
of  engines  having  what  is  termed  a  releasing-valve  gear. 

Crab-claw. — A  term  applied  to  the  pawls,  which  liberate  the 
valve-gear  of  engines  of  the  Corliss  type  from  the  influence  of 
the  eccentric,  when  the  point  of  cut-off  is  reached. 

Valves  and  Cocks  Connected  with  Engines  and  Boilers, 

The  valves  and  cocks  on  a  ship's  side,  in  the  engine,  boiler-room, 
and  hold  of  a  steamship,  are  the  injection-,  main-,  bilge-,  discharge-, 
and  water-service  valves,  and  the  blow-off*-,  scum-,  and  ash-cocks. 

The  valves  on  a  marine  engine  that  can  be  worked  by  hand 
are  the  stop-,  safety-,  slide-,  throttle-,  starting-,  feed-,  and  suction- 
valves. 

The  valves  that  are  worked  by  the  motion  of  the  engine  are 
the  slide,  cut-off*,  or  expansion,  feed,  and  bilge-pump,  check,  and 
discharge  valves. 

The  valves  and  pipes,  through  Ahich  the  steam  passes  from  the 
boiler  to  the  condenser,  are  the  steam  stop-valve  on  the  boiler- 
dome,  the  steam-pipe,  the  throttle-valve,  the  slide-  or  poppet-valve 
in  the  steam-chest,  and  the  eduction-pipe  between  the  cylinder  and 
the  condenser. 

The  cocks  and  valves  through  which  the  injection  and  boiler 
20 


230 


THE   ENGINEER'S  HANDY-BOOK. 


feed-water  passes  in  jet-condensing  engines  are  the  sea-injection 
cock,  passing  through  the  ship's  side  to  the  rose-plate  in  the  con- 
denser, from  which  it  is  drawn  off  by  the  air-pump,  through  the 
foot-valve,  and  delivered  to  the  hot  well,  from  whence  the  quantity 
necessary  is  drawn  by  the  feed-pump,  and  forced  through  the 
check-valves  into  the  boiler. 


Fig.  2. 


The  above  cuts  represent  a  simple  method  of  ascertaining 
whether  a  slide-valve  is  w^ell  proportioned  or  not,  and  whether 
the  exhaust  opens  at  the  right  time,  too  soon,  or  too  late.  Dis- 
connect the  valve  from  the  rod  or  yoke,  and  take  two  parallel 
pieces,  J.  JL,  about  one-half  inch  thick  and  one  inch  wide;  though 
the  exact  width  or  thickness  is  immaterial.  Let  one  be  the  exact 
length  of  the  valve  in  the  direction  of  its  travel,  on  which  the 
width  of  the  exhaust  opening,  C,  in  the  valve-face  may  be  marked  , 
by  cutting  notches  with  a  penknife;  then  place  the  other  parallel 
piece  on  the  valve-seat,  and  mark  the  width  of  the  steam-ports? 
i>,  and  the  exhaust,  D.  Then  place  the  one  representing  the 
valve,  A,  in  the  centre  of  its  travel,  as  shown  in  Fig.  1,  and  ob- 
serve the  inside  and  outside  lap ;  next*  place  it  at  the  commence- 
ment of  its  stroke,  as  shown  at  F,  Fig.  2,  and  observe  the  amount 
of  exhaust  opening. 


THE   ENGINEER'S  HANDY-BOOK. 


231 


If  it  should  appear  that  the  valve  is  well  proportioned  for 
the  admission  of  the  steam,  and  that  the  exhaust  opens  too  late, 
the  difficulty  may  be  remedied  by  chipping  out  the  exhaust- 
opening  in  the  valve-face ;  or,  should  it  be  found  that  the  exhaust 
opens  too  early,  it  may  be  obviated  by  inserting  some  pieces  of 
brass  or  copper,  and  securing  them  to  the  valve  with  some  small- 
tap-bolts,  the  heads  of  which  may  be  riveted  down ;  after  which 
the  pieces  may  be  filed  and  scraped  down  to  correspond  to  the 
face  of  the  valve. 

Pipes. 

The  principal  pipes  connected  with  marine  engines  and  boilers 
are  the  main  steam-pipe,  donkey-pipe,  cylinder  jacket-pipe,  whistle- 
pipe,  the  steam  winch-pipe,  ballast  engine-pipe,  feed-pipes,  donkey 
feed-pipes,  donkey  suction-pipes,  and  a  hot-well  connection-pipe, 
circulating  water-pipes,  feed  suction-pipes,  air-pump  discharge, 
bilge-discharge,  bilge-suction,  bilge-injection,  cylinder  drain-pipes, 
slide-jacket  drain-pipes,  and  steam-jacket  drain-pipes,  blow-oflf-  and 
scum-pipes,  waste-steam  pipe,  cooling-pipe,  water-service  pipes. 

The  pipes,  cocks,  and  valves  used  in  connection  with  the  loco- 
motive are  the  arch-pipes,  blast-pipes,  connecting-pipes,  oil-pipes, 
steam-gauge  pipe,  blower-pipe,  feed-pipes,  heater-pipes,  lifting-pipe, 
sand-pipes,  steam-pipe,  throttle-pipe,  blow-off  cocks,  check-valve, 
cylinder-cocks,  feed-water  cocks,  frost-cocks,  gauge-cocks,  heater- 
cocks,  mud-cock,  pet-cock,  safety-valve,  slide-valve,  stop-cock,  stop- 
valves,  and  throttle-valve. 

The  pipes,  cocks,  and  valves  used  in  connection  with  station- 
ary engines  are  the  steam-pipe,  exhaust-pipe,  feed-water  pipe, 
blow-off  pipe,  drip-pipes  from  cylinder,  drip-pipe  from  heater, 
steam-gauge  pipe,  slide,  poppet,  or  rotary  steam-valves,  globe- 
valves  on  steam-  and  water-pipes,  check-valves,  stop-cocks  on  blow- 
off  pipe,  bib-cocks,  drips,  etc. 

Check-valves  are  placed  on  the  connections  between  steam- 
boilers  and  the  pump  or  injector,  by  which  they  are  fed  to  resist 
the  pressure  from  the  boiler. 


232 


THE    engineer's  HANDY-BOOK. 


The  Wells  Two-Piston  Balance-Engine. 

The  cut  on  opposite  page  represents  the  Wells  Two-Piston 
Balance-Engine,  which,  the  inventor  claims,  possesses  features  in 
point  of  efficiency  and  economy  which  place  it  on  a  par  with  some 
of  the  most  improved  engines  in  the  country,  as  it  may  be  run  at 
a  much  higher  velocity,  and,  in  consequence  of  its  greater  capac- 
ity, is  more  efficient  than  any  single-piston  engine  in  use  at  the 
present  day.  The  weight  and  momentum  of  the  reciprocating 
parts  being  equal  in  opposite  directions,  the  action  is  perfect 
without  lead,  which  results  in  a  great  saving  of  steam  ;  and  as  the 
force  is  applied  on  opposite  sides  of  the  shaft,  and  both  cranks 
travel  in  the  same  direction,  the  thrust  due  to  a  single  crank,  is 
avoided.  Moreover,  because  all  the  force  of  the  steam  on  the 
cranks  is  exerted  in  torsion,  there  is  no  strain  on  the  housing  or 
foundation ;  hence  it  requires  only  a  slight  foundation.  They  have 
been  frequently  run  at  a  piston  speed  of  1000  revolutions  per  min- 
ute, without  any  perceptible  jar  to  the  engine  or  vibration  in  the 
building. 

It  is  further  claimed  that  the  advantages  of  high  piston  speed, 
and  the  benefits  to  be  derived  from  expansion,  are  more  fully 
realized  in  this  engine ;  and  that  the  condensation  is  less  than  it 
possibly  can  be  in  any  single-piston  engine.  Besides,  the  weight 
of  these  engines  is  only  about  one-fourth  that  of  ordinary  engines 
of  the  same  power ;  and,  in  consequence  of  the  absence  of  all 
vibration  while  they  are  working,  they  can  be  placed  in  any  room 
in  a  building  without  inconvenience  or  annoyance,  and  are  pecu- 
liarly adapted  to  yachts  and  other  pleasure  boats.  The  cut  on 
page  234  shows  a  section  of  the  same  engine :  A  A  and  B  B  des- 
ignate the  steam-  and  exhaust-ports  ;  C  C,  the  piston-heads ;  D,  the 
middle  piston-rod,  which  works  through  the  middle  piston-head ; 
E  E,  the  outside  piston-rods ;  F,  the  middle  connecting-rod ;  G  G, 
the  outside  connecting-rods;  H  Hy  the  middle  crank-arms;  //, 
the  outside  crank-arms  ;  J,  the  shaft ;  IT  shows  the  line  on  whicb 
the  opposing  strains  are  exerted. 


THK    engineer's   HANDY-BOOK.  233 


THE   ENGINEER'S  HANDY-BOOK. 


235 


Steam  is  admitted  sirftultaneously  to  both  ends  of  the  cylinder, 
and  exhausted  in  the  ordinary  way  by  means  of  a  slide-valve. 

But  as  the  piston  is  one  of  the  most  important  parts  of  a  steam- 
engine,  and  is  oftener  a  source  of  annoyance  and  waste  than  any 
other  adjunct  of  the  machine,  it  is  extremely  doubtful  if  the 
economy  of  any  engine  can  be  increased  by  the  use  of  two  pistons. 
Such  engines,  instead  of  being  economical,  are  more  frequently  a 
source  of  expense  and  annoyance. 

Instructions  for  the  Care  of  Steam-Engines. 

Never  allow  an  engine  to  become  dirty,  as  thorough  cleaning 
requires  no  great  amount  of  labor.  An  engine  which  has  always 
been  kept  clean,  protected  from  rust  and  not  abused  in  any  way, 
is  worth,  when  second-hand,  very  much  more  than  another  which 
has  had  little  attention,  been  allowed  to  rust,  and  to  take  care  of 
itself  generally. 

A  handsomely  kept  engine,  with  all  its  parts  clean  and  in  good 
order,  furnishes  stronger  evidence  of  an  engineer's  capabilities 
than  a  volume  of  written  recommendations. 

Never  depend  entirely  on  patent  oil-cups,  as  they  either  feed 
too  fast  or  not  at  all.  There  is  generally  too  much  oil  wasted  on 
engines.  What  is  needed  is  a  small  quantity  at  the  right  time, 
and  in  the  right  place,  and  all  that  is  not  essential  is  wasted. 

Do  not  allow  the  packing  to  become  hard  and  dry  in  the  stuffing- 
boxes,  as  under  such  circumstances  it  has  a  tendency  to  cut  and 
flute  the  rods. 

Never  strike  any  part  of  an  engine  with  the  face  of  the  hammer 
or  head  of  a  monkey-wrench,  as,  in  consequence  of  their  being 
headed  with  steel,  they  have  a  tendency  to  bruise  the  parts  and 
disfigure  the  engine. 

Never  set  steam-packing,  cotton-waste,  tops  of  oil-cups,  or 
anything  that  is  to  be  used  round  the  cylinder,  valves,  piston-rod, 
or  bearings  of  steam-engines,  on  the  floor,  as  they  will  invariably 
pick  up  sand  or  grit,  which  injure  the  rubbing  and  revolving  sur- 
faces with  which  they  come  in  contact. 


236 


THE   ENGINEER'S  HANDY-BOOK. 


When  practicable,  piston  and  valve-rod  packing  should  be  ap- 
plied when  the  stufRng-boxes  and  rods  are  cold.  The  best  pack- 
ing is  often  destroyed  through  ignorance  or  want  of  skill. 

Almost  any  packing  may  be  improved  by  being  soaked  in  bees- 
wax, tallow,  and  black-lead,  before  being  used. 

Gum-joints  that  require  to  be  frequently  taken  apart,  should  be 
coated  with  chalk  before  being  placed  between  the  flanges ;  this 
prevents  the  gum  from  adhering  to  the  metal  and  being  destroyed 
when  the  joint  is  taken  apart.  All  gum-joints  located  in  the  water- 
space  of  steam-boilers  should  be  coated  with  black-lead  and  tal- 
low before  being  put  together.  This  has  the  effect  of  preventing 
the  sulphur  of  the  gum  from  attacking  the  metal  and  destroying 
the  surfaces. 

When  it  becomes  necessary  to  stop  an  engine  with  a  heavy  fire 
in  the  furnace,  place  a  layer  of  fresh  coal  on  the  fire,  shut  the 
damper,  and  start  the  injector  or  pump,  for  the  purpose  of  keeping 
up  the  circulation  in  the  boiler. 

Always  see  that  the  cylinder  drain-cocks  are  open  when  the 
engine  is  standing  still,  and  never  close  them  till  after  starting. 

Never  admit  the  tallow  to  the  cylinder  until  the  engine  is  fairly 
under  way,  and  the  cylinder  drain-cocks  closed. 

Always  start  an  engine  slowly,  and  allow  it  to  come  up  to  speed 
gradually. 

Before  starting  an  engine,  always  warm  up  the  cylinder  by  ad- 
mitting the  steam  to  both  ends  ;  if  a  marine  engine,  see  that  every- 
thing is  clear  of  the  engines  and  propeller,  and  that  the  cocks  and 
valves  are  all  right. 

Whenever  an  engine  is  stopped  for  any  length  of  time,  examine 
all  its  parts,  for  the  purpose  of  seeing  if  they  are  in  good  order. 

In  cases  of  extreme  heating,  slack  up  on  the  keys  and  gibs, 
permit  them  to  run  loose  for  a  time,  and  then  take  up  the  lost 
motion  gradually. 

Examine  the  piston-packing  in  the  cylinder  frequently,  for  the 
purpose  of  seeing  that  it  is  tight  and  in  good  order. 

Keep  the  cylinder  and  steam-pipes  well  covered  with  some  good 


THE   ENGINEER\s    HANDY-BOOK.  237 

non-conductor,  to  counteract  the  cooling  effect  of  the  atrnos- 
yl^ero. 

Whenever  a  clicking  noise  is  heard  in  the  cylinder,  open  the 
cylinder  drain-cocks,  and  allow  the  water  to  escape  ;  then  let  them 
remain  open  until  the  cylinder  works  dry  steam. 

In  giving  instructions  for  the  care  and  management  of  steam- 
engines,  too  much  stress  cannot  be  laid  upon  the  injunction,  "  Keep 
your  steam  always  at  the  same  pressure,"  as,  although  all  engines 
employed  for  manufacturing  purposes  have  governors,  they  are 
not  always  reliable  or  capable  of  meeting  the  requirements  of 
varying  steam-pressures  and  varying  loads ;  consequently,  if  the 
steam  is,  through  neglect,  permitted  to  rise  above  the  working 
pressure,  the  engine  will  increase  its  speed,  which  will  induce  a  loss 
of  steam,  as  every  revolution  above  the  speed  at  which  the  engine 
was  intended  to  run,  and  at  which  the  machinery  is  geared  for  the 
manufacture  of  the  different  materials,  is  a  waste;  and  every  revo- 
lution the  engine  falls  below  the  regular  speed  is  a  loss  of  produc 
tion. 

Piston-Rod  and  Talve-Rod  Tacking,  and  How  to  Use  it. 

Probably  no  part  of  the  steam-engine  is  more  frequently  out 
of  order  than  the  piston-rod  and  valve-rod  packing.  This  may  be 
attributed  to  various  causes,  viz.,  such  as  the  speed  of  the  engine ; 
whether  it  is  in  line  or  not ;  whether  the  piston  leaks  or  not the 
condition  of  the  piston-rod  ;  the  pressure  of  the  steam  ;  the  clear- 
ance in  the  cylinder,  and  the  character  or  quality  of  the  material 
of  which  the  packing  is  composed,  as  well  as  the  manner  in  which 
it  is  applied,  and  how  it  is  treated  afterwards. 

If  the  engine  is  out  of  line,  the  piston-rod  will  crowd  the  pack- 
ing to  one  side  or  the  other  at  certain  points  of  the  stroke ;  if  the 
piston-  and  valve-rod  are  badly  fluted,  the  steam  will  escape  through 
the  grooves  ;  if  the  piston-packing  leaks  in  the  cylinder,  it  will  be 
impossible  to  keep  the  packing  around  the  rod  tight,  in  conse- 
quence of  the  cushioning  induced  by  the  leakage.  If  the  distance 
between  the  piston  and  cylinder-head  is  not  sufiicient,  the  steam 


238 


THE   ENGINEER'S  HANDY-BOOK. 


will  escape  through  the  stuffing-box  as  the  engine  approaches  the 
centres ;  if  the  rings  of  the  material  are  cut  too  long,  they  will 
not,  when  screwed  up,  hug  the  rod,  and,  as  a  result,  leakage  will 
occur;  if  too  short,  the  steam  will  insinuate  itself  between  them, 
and  cause  leakage ;  if  the  material  is  not  of  the  proper  size  to  fill 
the  cavity  between  the  rod  and  the  box,  it  will  leak,  however 
tightly  it  may  be  screwed  up ;  if  the  packing  is  screwed  up  too 
tight  at  first,  the  heat  induced  by  the  friction  will  soon  destroy  its 
elasticity,  and  leakage  will  be  the  result ;  if  the  engine  runs  at  a 
very  high  speed,  the  packing  will  deteriorate  faster  than  if  the 
speed  is  moderate ;  and  if  the  pressure  is  high,  the  temperature 
due  to  the  pressure  will  have  a  tendency  to  destroy  the  packing. 
Another  cause,  and  indeed  one  of  the  main  causes  which  induce 
leaking  around  piston-  and  valve-rods,  is  the  want  of  depth  of  the 
stuffing-boxes  of  some  engines,  which  will  not  receive  more  than 
two  rings  of  packing ;  as  a  result,  they  are  continually  leaking 
around  the  rod,  whereas,  if  the  box  is  sufficiently  deep  to  admit 
of  four  rings,  the  leakage  nuisance  would  be  obviated. 

A  great  variety  of  materials  is  in  use  for  packing  purposes, 
soap-stone,  paper,  india-rubber,  asbestos,  tin-foil,  webbing,  wire- 
cloth,  metallic  packing,  etc.,  each  of  which  possesses  merit  peculiar 
to  itself,  but,  like  governors,  and  many  other  important  adjuncts 
of  the  steam-engine,  not  one  of  them  was  ever  known  to  answer 
every  place,  or  give  satisfaction  under  all  circumstances.  This 
arises  from  the  fact  that  our  investigation  has  not  been  such  up 
to  the  present  time,  on  this  subject,  as  to  enable  us  to  decide  which 
material  will  give  the  most  satisfaction  under  the  most  varying 
circumstances  ;  besides,  the  best  material  may  be  rendered  useless 
in  a  comparatively  short  time  through  ignorance,  while  an  inferior 
quality  may  render  good  service  by  being  intelligently  treated. 

The  following  instructions  may  be  of  use  to  those  who  have  not 
had  much  experience  in  packing  piston-  and  valve-rods :  Insert  as 
much  packing  into  the  box  as  will  just  allow  the  gland  to  enter; 
then  screw  it  up  solid ;  after  which  the  nuts  should  be  slacked  for 
the  purpose  of  allowing  the  packing  to  swell  when  exposed  to  the 


THE   engineer's  HANDY-BOOK. 


239 


steam ;  if  leakage  occurs,  screw  them  up  gradually  and  evenly, 
until  it  stops.  If  the  leakage  is  excessive,  after  a  sufficient  quan- 
tity is  inserted  in  the  box,  do  not  continue  to  screw  it  up,  as  the 
heat  of  the  rod  will  soon  destroy  the  packing.  It  is  always  better 
to  stop  the  engine,  if  practicable,  remove  two  or  three  pieces,  and 
replace  them  again  in  opposite  positions,  when  in  all  probability 
the  leakage  will  cease.  Never  use  any  old  file  or  any  rough  in- 
strument to  remove  the  packing  from  the  boxes,  as  they  have  a 
tendency  to  abrade  or  flute  the  rods,  and  cause  leakage.  Every 
engineer  and  steam-user  should  provide  himself  with  suitable 
tools  for  removing  the  old  packing  from  the  boxes  and  inserting 
the  new.  To  find  the  proper  diameter  of  the  packing  for  any 
stufiing-box :  Measure  the  diameter  of  the  rod,  and  also  the  gland 
or  stem  of  the  stufBng-box,  and  half  the  difference  between  the 
two  will  be  the  proper  size  of  the  packing. 

Numerous  attempts  have  been  made  at  different  times  to  sub- 
stitute a  metallic  piston-  and  valve-rod  packing  for  the  various 
fibrous  packings  now  in  use  which  would  be  more  durable,  and 
at  the  same  time  involve  no  more  cost;  but  up  to  the  present  time 
none  of  these  attempts  have  been  crowned  with  success.  This 
may  be  attributed  to  various  causes,  such  as  the  condition  of  the 
piston-rod,  whether  it  is  fluted  or  not ;  whether  the  engine  is  in 
line  or  not ;  the  condition  of  the  steam-packing  in  the  cylinder ; 
the  depth  of  the  stuffing-box,  whether  it  is  leaky  or  not;  the 
clearance  space  between  the  piston-  and  cylinder-heads  when  the 
crank  is  at  the  centre;  the  amount  of  back  pressure;  the  difficulty 
of  manufacturing  the  metallic  packing  in  sizes  to  meet  all  the 
vagaries  of  that  class  of  steam-engine  builders  who  pay  no  atten- 
tion to  good  proportions,  and  who  make  the  stuffing-boxes  odd 
sizes;  the  condition  and  shape  of  a  stuffing-box  to  which  it  has  to 
be  applied ;  the  ignorance  displayed  in  its  care  and  management, 
as  well  as  a  disposition  on  the  part  of  those  who  have  it  in  charge  to 
cry  down  every  new  innovation  in  steam  engineering,  and  to  ridi- 
cule every  adjunct  of  the  steam-engine  and  boiler  that  requires  any 
special  attention,  however  great  a  safeguard  or  economizer  it  may  be. 


240 


THE   engineer's  HANDY-BOOK, 


WardwelPs  High-Pressure,  Valveless  Engine. 

The  cut  on  page  241  represents  Wardwell's  Valveless  Engine. 
As  will  be  observed,  it  is  a  horizontal  engine,  with  one  end  of  a 
girder  frame  bolted  to  and  supporting  the  cylinder,  and  the  other 
supporting  the  pillow-block.  The  pillow-block  brasses  are  pro- 
vided with  side  adjustment  wedges,  operated  from  the  top  face  of 
the  cap  by  bolts  and  nuts.  The  cross-head  has  V-shaped  bear- 
ings, top  and  bottom,  with  a  wrist-pin  providing  journal-bearings 
for  the  fork  end  of  the  connecting-rod.  The  straps  at  these  ends 
of  the  rod  are  provided  with  the  ordinary  gibs  and  keys.  At  the 
crank-pin  end,  however,  the  strap  is  secured  to  the  rod  by  a  bolt 
passing  through  the  strap,  the  key  merely  serving  to  adjust  the 
brasses.  The  piston  passes  a  working  fit  through  the  cross-head, 
being  secured  at  each  end  by  jamb-nuts,  by  which  arrangement 
any  lateral  play  of  the  piston-rod  in  the  cross-head  is  prevented ; 
but  at  the  same  time  the  rod  rotates  in  the  latter.  To  the  ex- 
treme end  of  the  piston-rod,  after  it  has  passed  through  the  cross- 
head,  there  is  keyed  fast  a  section  of  a  bevel- wheel  containing  5 
teeth,  which  gears  into  another  containing  4  teeth ;  this  latter  sec- 
tion being  bolted  fast  to  the  inside  of  one  of  the  fork-arms  of  the 
connecting-rod ;  the  outside  arm  being  selected  as  affording  the 
best  advantages  for  adjustment.  When  the  connecting-rod  is  at- 
tached to  the  crank-  and  cross-head,  and  steam  admitted  to  the 
cylinder,  a  semirotary  movement  takes  place  in  regular  order,  and 
as  the  stroke  proceeds,  the  steam  passages  are  so  arranged  that 
steam  can  be  admitted,  cut  off,  and  exhausted  at  any  desired 
point  of  the  stroke.  It  is  obvious,  however,  that  to  accomplish 
this  the  piston-head  in  the  cylinder  must  be  extra  long  in  propor- 
tion to  the  stroke. 

The  piston  is  solid,  similar  to  a  plunger,  and  is  a  neat  working 
fit  in  the  bore  of  the  cylinder.  The  wear  is  provided  for  by  the 
insertion  at  each  end  of  the  piston-head  of  ordinary  spring  pack- 
ing-rings; and  to  take  up  wear  and  prevent  leakage  from  one  port 
to  the  other,  a  straight,  longitudinal,  spring  packing-piece  is  placed 


242 


THE   ENGINEER'S  HANDY-BOOK. 


between  the  steam  passages  in  the  piston-head,  thus  preventing 
the  escape  from  one  port  to  the  other.  The  steam-port  is  in  the 
centre  of  the  cylinder,  and  on  top.  The  steam  passages  in  the 
piston-head  commence  near  one  end,  and  run  along  the  circum- 
ferential surface,  in  a  longitudinal  but  curved  line,  so  that  the 
passage  will  remain  full  open  to  the  cylinder  steam-port,  notwith- 
standing the  rotary  motion  of  the  piston.  At  such  part  of  the 
stroke,  however,  at  the  point  at  which  the  steam  is  to  be  cut  off, 
the  steam  passage  turns  at  an  angle,  and  runs  round  nearly  one- 
half  the  perimeter  of  the  piston-head,  so  that  the  rotary  motion 
of  the  piston  during  the  remainder  of  the  stroke  is  insufficient  to 
permit  any  communication  between  the  cylinder-port  and  piston 
passages.  So  soon  as  the  piston-head  steam  passage  turns  the 
angle  above  noted,  the  longitudinal  movement  of  the  piston-head 
past  the  cylinder  steam-port  cuts  off  the  supply  of  steam,  and  the 
remainder  of  the  piston-stroke  is  performed  by  expansion.  The 
circumferential  direction  of  the  passage  above  referred  to  serves 
another  purpose  than  acting  as  a  cut-off,  in  that  it  enables  the 
same  passage  to  be  used  to  convey  the  steam  to  the  cylinder  ex- 
haust-port. After  the  steam  passage  has  taken  the  circumferential 
direction  referred  to,  it  continues  longitudinally  to  the  end  of  the 
piston-head ;  the  steam  passage,  while  isolated  from  the  cylinder 
steam-port,  comes  into  open  communication  with  the  cylinder  ex- 
haust-port, and  that  stroke  of  the  engine  is  completed.  For  the 
return-stroke,  a  similarly  arranged  passage  is  provided  in  the 
piston-head,  and  hence  the  piston  requires  but  two  passages, 
each  of  which  operates  alternately,  as  induction  and  eduction 
passages. 

There  were  three  of  this  description  of  engines  on  exhibitioi/ 
at  the  Centennial  Exposition,  which  attracted  considerable  atten- 
tion, in  consequence  of  the  arrangement  for  admitting  and  ex-^ 
hausting  steam  being  entirely  different  from  anything  heretofore? 
employed.  Such  engines  possess  no  practical  value,  their  chief 
interest  consists  in  the  novelty  of  the  arrangement. 


THE   ENGINEER^S  HANDY-BOOK. 


243 


Lubricants. 

To  understand  the  quantity  of  oil  required  for  steam-cylinders, 
slide-valves,  and  the  reciprocating  or  revolving  parts  of  steam- 
engines,  we  should  first  know  what  its  objects  are.  The  object  of 
oil  is  to  diminish  friction,  by  interposing  a  thin  film  between  the 
sliding  or  revolving  surfaces.  To  insure  perfect  lubrication,  the 
surfaces  must  be  kept  coated  at  all  times,  under  all  pressures  and 
velocities.  In  steam-engines  there  is  a  sliding  and  rotating  fric- 
tion, and  it  is  very  doubtful  if  any  one  kind  of  oil  is  perfectly 
suited  to  both.  Oil  has  no  tendency  to  improve  the  character  of 
a  bearing ;  its  functions  being  simply  to  keep  them  apart,  prevent 
heat,  and  diminish  friction. 

Temperature  exerts  a  very  important  influence  over  any  lubri- 
cant. A  thin  oil  has  a  tendency  to  run  off  too  fast,  while  a  thick 
one  is  not  sure  to  flow.  Tallow,  and  all  other  thick  and  greasy 
compounds,  are  exposed  to  the  same  objection,  as  the  bearing  gen- 
erally gets  hot  before  the  lubricant  begins  to  flow.  Besides,  what 
may  be  called  a  good  lubricant,  one  that  adheres  to  the  rubbing 
surfaces  under  ordinary  circumstances,  may  not  be  equally  well 
adapted  to  all  conditions,  as  the  area  of  the  bearing  surfaces  varies 
with  the  size  of  the  journals,  and  the  form  of  the  boxes,  which 
causes  a  difference  in  the  velocity  of  rotation.  From  this,  it  fol- 
lows, that  a  lubricant  that  would  be  retained  between  the  frictional 
surfaces  under  a  light  load,  would  be  entirely  pressed  out  under  a 
heavy  one. 

The  quantity  of  lubrication  that  the  cylinders  and  slide-valves 
of  any  engine  require,  depends  on  the  condition  of  the  engine,  the 
amount  of  work  it  is  performing,  and  on  the  pressure  and  tem^ 
perature  of  the  steam.  If  the  load  is  light,  the  pressure  low, 
and  the  engine  in  good  order,  very  little  lubrication  is  necessary; 
but  if  the  pressure  and  speed  are  high,  and  the  engine  is  working 
up  to  its  full  capacity,  the  cylinder  and  valves  will  require  to  be 
frequently  lubricated.  But  in  no  case  should  an  unnecessary 
quantity  be  used,  as  it  is  likely  to  produce  a  greater  evil  than  the 


244 


THE   ENGINEER\s  HANDY-BOOK. 


one  it  was  intended  to  remedy.  A  person  having  charge  of  steam 
machinery  should  understand  the  work  each  part  has  to  perform, 
the  speed  at  which  it  runs,  and  the  weight  it  has  to  sustain. 
Crank-pins  and  main-bearings  require  to  be  frequently  oiled ;  but 
the  condition  of  the  bearing  will  determine  the  quantity  of  lubri- 
cation needed.  What  is  needed  in  any  case  is  a  few  drops  of  good 
oil  applied  often.  It  may  be  safely  said  that  five  times  the  quan- 
tity  of  lubrication  is  used  on  the  revolving  and  rubbing  surfaces, 
and  in  the  valves  and  cylinder  of  steam-engines,  which  is  actually 
necessary. 

According  to  the  general  impression,  grease  or  animal  oil  is  a 
preserver  of  metal ;  but  experience  has  shown  that  it  is  more  fre- 
quently a  destroyer,  especially  of  the  cylinders,  pistons,  and  valves 
of  steam-engines.  The  reason  of  this  is,  that  vegetable  and  ani- 
mal fats  and  oils  contain  stearic,  megaric,  and  oleic  acids,  which, 
when  subjected  to  the  heat  of  high  pressure  steam,  that  frees  them 
from  their  base,  attack  the  metal  and  destroy  it.  This  applies  as 
well  to  oils  of  vegetable  as  to  oils  of  animal  origin,  as  fish  or 
sperm  oil.  On  removing  the  heads  of  steam-cylinders  and  the 
bonnets  of  steam-chests,  the  cylinders,  pistons,  and  steam-chests 
frequently  show  evidence  of  corrosion,  which  difiers  entirely  from 
that  of  ordinary  wear,  and  which  persons  unacquainted  with  the 
nature  and  effect  of  the  oil  and  grease  they  have  been  using,  are 
puzzled  to  account  for.  Oils  derived  from  petroleum  contain  no 
oxygen,  cannot  form  acid,  and  therefore  do  not  attack  metal. 
The  proof  of  this  may  be  found  in  the  fact,  that  such  oils  are  used 
in  surgical  operations,  and  for  cuts,  bruises,  and  abrasions,  with 
good  effect.  Oils  from  petroleum  are  produced  for  nearly  every 
mechanical  process,  as  well  as  for  the  cylinders  of  steam-engines, 
for  which  latter  purpose  animal  oils  were  considered  indispensable. 

At  a  recent  meeting  of  the  Railway  Master  Mechanics'  Associ- 
ation, at  St.  Louis,  a  report  was  presented  by  the  committee  on 
lubricants,  which  embodied  the  result  of  a  series  of  experiments 
made  for  the  purpose  of  testing  the  lubricating  qualities  of  differ- 
ent kinds  of  oil.    In  making  the  test,  56  drops  of  each  variety 


THE   engineer's  HANDY-BOOk' 


245 


or  oil  were  put  into  a  dynamometer,  which  was  run  at  35 'miles 
an  hour,  until  the  temperature  was  raised  from  60^  to  200*^  Fah. 
The  exact  number  of  revolutions  necessary  to  produce  this  change 
of  temperature  was  noted  in  each  case,  and  is  given  in  the  last 
column  of  the  following  table. 


Cost  per 
Gallon. 

Average  Rev- 
olutions. 

$1.25 

12-946 

Paraffin  e  

.28 

11-685 

Mecca  (black)  

.45 

9-982 

Manufactured  "J."  

.35 

9-653 

U  (C 

.90 

9-394 

.25 

9-187 

Neat's-foot  ,  . 

.85 

8-277 

.26 

7-915 

1.75 

7-912 

Tallow   

.70 

7-794 

No.  1  Lard  

.70 

7-377 

Manufactured  "D"  .... 

.25 

6-999 

a          it          a  j^yf 

.85 

6-798 

tc          «  *'J7"* 

.20 

6-121 

W.  Virginia  (reduced)    .    .  . 

.20 

4-770 

.20 

4-215 

It  has  lately  been  demonstrated  that  natural  petroleum  oils, 
when  thoroughly  freed  from  grit,  are  for  many  purposes  as  good, 
if  not  better,  than  sperm,  with  the  advantage  of  being  much 
cheaper ;  but  they  are  objectionable  in  consequence  of  their  lia- 
bility to  stain  bright  work  or  finished  machinery. 

It  is  not  by  any  means  uncommon  to  see  ignonint  and  inex- 
perienced persons  who  have  charge  of  steam-engines  pouring  oil 
on  cross-head  guides  and  piston-rode  every  five  minutes  during 
the  day.  This  is  immediately  rubbed  off  by  the  shoes  or  the 
piston-rod  packing,  without  rendering  any  service,  which  is  a 
wilful  waste  of  the  necessary  supplies  in  their  charge,  and  has  a 
tendency  to  lessen  the  profits  of  the  establishment. 
21* 


246  THE   ENGINEER'S  HANDY-BOOK. 

Questions : 

THE  ANSWERS  TO  WHICH  WILL  BE  FOUND  IN  THE  TEXT. 

What  are  the  objects  and  functions  of  the  bed-plate  as  a  part 
of  the  steam-engine  ? 

Give  the  rule  for  finding  the  necessary  strength  of  a  bed-plate 
/or  any  given  speed  and  pressure. 

State  the  rule  for  finding  the  proper  thickness  of  a  steam-cyl- 
inder of  any  diameter. 

Give  the  rule  for  finding  the  diameter  of  a  cylinder  for  any 
given  horse-power. 

Give  the  rule  for  finding  the  cubic  contents  of  a  steam-cylinder 
of  any  given  diameter. 

State  the  rule  for  finding  the  quantity  of  steam  that  any  engine 
will  use  at  each  stroke  of  the  piston. 

Give  the  necessary  strength  of  cylinder-head  bolts. 

What  are  the  objects  and  functions  of  the  pistons  of  steam- 
engines,  and  what  qualities  should  they  possess  ? 

Give  the  proportions  of  piston-rods  for  condensing  and  non- 
condensing  engines,  according  to  the  be$t  modern  practice. 

Give  the  units  of  horse-power  for  various  piston  speeds. 

Give  the  pcpportions  of  steam-  and  exhaust-pipes  according  to 
/he  best  modern  practice. 

What  proportion  should  the  diameter  of  the  valve-rod  bear  to 
that  of  the  cylinder? 

Give  the  proper  length  and  width  of  the  cross-head  bearings. 
What  is  the  meaning  of  the  term  eccentric? 


THE   engineer's   HANDY-BOOK.  247 

What  are  the  functions  of  the  craok,  and  what  change  of  mo- 
tion does  it  induce? 

Explain  the  cause  of  the  variation  of  the  piston  in  the  cylinders 

of  steam-engines  when  their  cranks  are  at  half-stroke. 

Give  the  rule  for  finding  the  position  of  the  piston  in  the  cyl- 
inder when  the  crank  is  at  half-stroke. 

Is  there  any  loss  of  power  incurred  in  the  employment  of  a 
crank  as  a  mechanical  device  for  converting  reciprocating  into 
rotary  motion  ? 

Give  the  rule  for  finding  the  necessary  proportions  of  crank- 
pins  for  any  engine. 

Give  the  proportion  of  the  crank-shaft  and  main-bearings  ac- 
cording to  the  best  modern  practice. 

Give  the  proper  proportions  of  gibs,  keys,  and  straps  for  any 
engine. 

Why  is  the  strap  thicker  at  the  slot  than  at  the  part  w^hich  en- 
circles the  box  ? 

What  are  the  functions  of  the  link? 

What  is  the  meaning  of  the  term  "  radius  of  the  link  "  ? 

Describe  the  mechanism  of  the  various  links  employed  as  a 
reversing-gear  for  steam-engines. 

What  is  the  object  of  the  fly-wheel  ? 

Give  the  rule  for  finding  the  proper  weight  of  fiy-wheel  for  any 
engine,  speed  and  pressure  being  given. 

What  are  the  functions  of  the  steam-engine  governor  ? 

Give  the  rule  for  finding  the  proper  size  of  governor-pulleys. 


248  THE  engineer's  handy-book. 

Give  the  most  approved  method  of  counterbalancing  the  re- 
ciprocating parts  of  steam-engines. 

What  are  the  most  common  causes  of  heating  in  the  journals 
of  steam-engines? 

What  are  the  uses  and  functions  of  the  slide-valve? 

Explain  the  advantages  and  disadvantages  of  the  slide-valve 
AS  contrasted  with  those  of  other  forms. 

Explain  the  action  of  poppet-  or  conical-valves. 

What  are  the  meanings  of  the  terms  lap  and  lead  on  the  valve? 

What  is  the  meaning  of  the  term  loss  of  lead  f 

What  is  meant  by  the  terms  valve-seat  and  valve-face? 

Explain  the  meaning  of  the  terms  valve-circle  and  valve-stroke. 

How  would  you  proceed  to  ascertain  the  amount  of  lap  and 
lead  on  a  slide-valve  without  opening  the  steam-chest  ? 

Give  the  meaning  of  the  term  cut-off,  and  the  amount  of  lap 
required  to  cut-off  at  different  points  of  the  stroke. 

State  the  most  economical  point  in  the  stroke  at  which  to  cut 
off  the  steam,  and  demonstrate  it  by  an  example. 

What  is  meant  by  friction  when  applied  to  slide-valves? 

How  would  you  proceed  to  set  the  valves  of  a  steam-engine? 

Is  the  friction  of  a  perfectly  fitting  slide-valve  more  or  less  than 
that  of  an  imperfectly  fitting  one  ? 

Give  the  names  of  the  different  valves  and  valve-gear  employed 
i6r  the  admission  and  escape  of  the  steam  to  and  from  the  cyl- 
inders of  steam-engines. 


THE  i:ngineer's  handy-book.  249 

Give  the  technical  terms  as  applied  to  the  valve-gear  of  steam- 
engines. 

Give  the  names  of  the  various  valves  and  cocks  in  use  on  dif- 
ferent steam-engines  and  boilers. 

Give  the  names  of  the  various  pipes  in  connection  with  differ* 
ent  kinds  of  steam-engines. 

Explain  the  meaning  of  the  term  valve-gear. 

In  what  condition  should  an  engine  be  kept? 

What  is  the  best  evidence  of  an  engineer's  capabilities  ? 

What  dependence  should  be  placed  on  patent  oil-cups? 

In  what  condition  should  the  packing  in  the  piston-  and  valve- 
rod  boxes  be  kept  ? 

What  is  the  objection  to  striking  any  part  of  an  engine  with 
the  face  of  a  hammer  or  head  of  a  monkey-wrench  ? 

What  is  the  objection  to  placing  piston-rod  packing  or  cotton 
waste  on  the  floor  ? 

When  should  piston-  and  valve-rod  packing  be  •applied? 

In  what  manner  may  piston-  and  valve-rod  packing  be  improved? 

How  should  gum-joints  be  treated,  which  must  of  necessity  be 
frequently  broken  ? 

What  precaution  should  an  engineer  take,  when  it  becomes 
necessary  to  stop  an  engine  with  a  heavy  fire  in  the  furnace? 

How  should  the  cylinder  drip-cocks  be  kept,  when  an  engine  is 
stopped  ? 

When  should  the  tallow  or  any  other  lubricant  be  admitted  to 
the  cylinder  ? 


250         THE  engineer's  handy-book. 
How  should  an  engine  be  started  ? 

What  precaution  should  an  engineer  take  before  starting  an 
engine  ? 

What  course  should  an  engineer  pursue  when  it  becomes  neces- 
sary to  stop  for  any  length  of  time  ? 

What  course  should  be  adopted  in  case  of  extreme  heating  in 
any  of  the  revolving  parts  of  an  engine? 

How  should  the  piston-packing  in  the  cylinder  be  treated? 

What  are  the  best  means  of  protecting  the  cylinder  and  steam- 
pipes  from  the  effects  of  the  atmosphere  in  order  to  diminish 
radiation  and  condensation? 

What  course  should  be  adopted  when  a  clicking  sound  is  heard 
in  the  cylinder? 

Why  is  it  very  important  that  the  steam  pressure  should  be 
kept  uniform  ? 

Give  the  reasons  why  the  piston-  and  valve-rod  packing  is  so 
frequently  out  of  order. 

Explain  the  best  method  of  using  piston-  and  valve-rod  packing. 

What  is  the  best  course  to  adopt  when  excessive  leakage  oc- 
curs ? 

How  should  piston-  and  valve-rod  packing  be  kept? 

Give  the  rule  for  finding  the  right  diameter  of  packing  for  any 
stuffing-box. 

What  is  the  object  of  lubrication  ? 

What  effect  has  temperature  on  lubricants? 

What  conditions  influence  the  amount  of  lubrication  required 
for  any  engine  ? 


THE   engineer's  HANDY-BOOK. 


251 


PART  FOURTH. 


The  Steam-Engine  Indicator:  Its  Invention  and 
Improvement. 

Perhaps  no  device,  in  the  entire  range  of  mechanical  inventions, 
nas  aided  so  much  in  developing  and  perfecting  the  steam-engine 
as  the  indicator. 
This  arises  from  the 
fact  that  no  otlier  in- 
vention yet  brought 
forward  pertaining 
to  the  science  of 
steam  engineering 
can  read  the  inner 
workings  of  a  steam- 
engine,  point  them 
out  with  unerring 
accuracy,  and  dis- 
cover the  sources  of 
waste  in  it.  Conse- 
quently, its  import- 
ance cannot  be  too 
highly  estimated, 
and  its  use  too  much 
encouraged  and  ex- 
tended in  all  classes 
of  steam-engines. 

The  steam-engine  indicator  is  said  to  have  been  invented  by 
James  Watt,  which  is  rather  doubtful;  and,  as  Watt  received 
credit  for  many  things  he  never  invented,  it  is  not  to  be  won- 
dered at  that  the  invention  of  the  indicator  has  been  attributed 
to  him.    Be  that  as  it  may.  Watt's  indicator,  though  very  im- 


252 


THE   ENGINEER'S  HANDY-BOOK. 


perfect,  answered  for  engines  travelling  at  a  piston  speed  of  about 
150  feet  per  minute,  and  for  pressures  averaging  7  lbs.  above 
atmosphere,  which  he  thought  was  the  fastest  speed  and  the  highest 
pressure  that  would  ever  be  needed.  But  experience  soon  demon- 
strated that  the  highest .  economy  was  attained  with  high  piston 
speeds  and  correspondingly  high  pressures,  and,  •  as  a  result, 
Watt's  indicator  proved  to  be  unsuitable  for  these  conditions. 
The  requirements  of  such  an  instrument  were  more  fully  appre- 
ciated by  McNought,  of  Glasgow.  The  world  is  more  indebted 
to  him  for  improvements  in  the  steam-engine  indicator  than  to 
any  one  previous  to  his  time. 

The  indicator  was  further  improved  by  Hopkinson,  Stillman, 
and  others ;  but  these  improvements  were  not  in  the  mechanical 
design  or  arrangement  of  its  working  parts,  but  rather  in  the 
accuracy  and  refinement  of  the  workmanship  employed  in  its 
construction,  as  the  mechanical  principles  embodied  in  the  Watt 
indicator  were  continued  in  them  all.  They  consisted  of  an  up- 
right cylinder,  into  which  a  piston  was  accurately  fitted.  To  the 
piston-rod  a  spiral  spring  was  attached,  to  resist  the  steam  and  the 
vacuum  when  acting  against  it.  The  pencil  was  also  attached  to 
the  piston-rod  ;  the  result  of  which  was  that  the  piston,  piston-rod, 
and  spring  had  the  same  movements  as  the  pencil.  With  such 
instruments  the  vibration  of  the  piston  was  so  great  as  to  render 
them  totally  unreliable  with  fast  running  engines,  or  when  steam 
was  worked  expansively. 

Gooch  was  the  first  inventor  that  gave  the  pencil  a  greater 
range  of  movement  than  the  piston.  In  his  instrument  the  cyl- 
inder was  placed  horizontally,  and  when  its  piston  was  subjected 
to  pressure  it  compressed  two  elliptic  springs.  The  top  of  his 
piston-rod  was  connected  to  the  short  arm  of  a  lever,  to  the  long 
arm  of  which  the  pencil  was  attached,  thus  giving  considerably 
more  motion  than  could  be  obtained  by  any  former  instrument 
The  pencil  moved  in  the  arc  of  a  circle  instead  of  a  straight  line. ' 
The  diagram  was  traced  on  a  web  of  paper  while  it  was  unwound 


THE    engineer's  HANDY-BOOK. 


253 


from  one  drum  and  wound  upon  another.  This  arrangement  ad- 
mitted of  a  succession  of  diagrams  being  taken  without  any  in- 
termediate manipulation  of  the  instrument.  The  communication 
between  the  indicator  and 
the  steam-cylinder  was  closed 
by  a  slide-valve  instead  of  a 
cock.  But  as  the  principle 
of  working  steam  expan- 
sively became  almost  uni- 
versal, an  instrument  more 
reliable  than  any  of  these 
previously  mentioned  be- 
came a  necessity  of  the 
times,  and  such  was  found 
in  the  Richards'  Indicator. 
In  this  instrument  the  fol- 
lowing construction  and  pro- 
portions have  been  adopted, 
and  adhered  to  from  the 
first.  The  area  of  the  piston 
is  ^  a  square  inch,  the  di- 
ameter of  which  is  very 
nearly  of  an  inch,  or, 
more  exactly,  '79  inch.  The 
length  of  the  long  arm  of 
the  lever,  to  which  the  rod 
of  the  piston  is  attached,  is 
3  inches,  and  the  distance 
from  the  pivot  of  the  lever 
to  the  point  of  attachment  of  the  piston  is  |  of  an  inch,  thus  giv- 
ing the  free  end  of  the  lever,  and  with  it  the  pencil,  four  times 
the  movement  of  the  piston.  The  secondary  lever  is  equal  in 
length  to  the  first,  and  the  link  which  connects  the  two,  and  which 
carries  the  pencil  at  its  centre,  is  1*^-  inches  long.  These  propor- 
22 


Section  of  the  Indicator. 


254 


THE   engineer's  HANDY-BOOK 


tions  give  a  practically  straight  pencil  movement  for  a  distance 
of  2}  inches. 

The  indicator  was  further  improved  by  Harris  Tabor,  (cuts 
of  whose  instrument  may  be  seen  on  pages  260  and  261 ;)  but 

more  recent  im- 
provements made  in 
the  indicator  have 
been  effected  by 
George  H.  Crosby, 
a  mechanical  en- 
gineer of  Boston, 
Mass.  It  has  appa- 
rently been  the  aim 
of  Mr.  Crosby  to 
avoid  unnecessary 
weight  in  the  recip- 
rocating parts,  to  in- 
sure correctness  of 
action,  and  to  so  sim- 
plify the  method  of 
manipulating  the 
instrument  as  to 
bring  it  within  the 
understanding  of 
engineers  of  limited 
education  and  per- 
sons of  ordinary 
intelligence.  In 
these  objects  he 
seems  to  have  been 
partially  successful, 
as  the  Crosby  Indicator  is  an  improvement,  in  some  respects, 
on  other  devices  of  the  kind  in  use;  as  it  is  reliable  in  its 
recordings,  whether  employed  for  taking  diagrams  from  auto- 
matic cut-off,  throttling,  simple,  compound,  fast-  or  slow-run- 


Crosby's  Improved  Indicator. 


THE   ENGINEER\s  HANDY-BOOK. 


255 


ning  engines;  as  it  is  free  from  some  objectionable  features 
in  other  instruments, 
which  render  the  dia- 
grams taken  by  them 
erroneous.  In  the  con- 
ception of  this  instru- 
ment, the  inventor  seems 
to  have  predetermined 
many  of  the  circum- 
stances, emergencies, 
and  requirements  that 
might  possibly  arise  in 
the  use  of  the  indicator, 
and  provided  for  them. 

The  advantages  of 
the  Crosby  Indicator 
are,  that  the  parallel 
motion  is  not  a  geomet- 
rical approximate  imi- 
tation of,  but  a  true 
motion;  that  the  motion 
of  the  pencil  is  a  uni- 
form multiplication  of 
the  piston  of  the  indi- 
cator, and  is  solely  con- 
trolled by  the  motion  of 
the  piston-rod ;  and  that 
there  are  no  guiding- 
slots,  either  straight  or 
curved,  to  induce  fric 
tion;  that  there  is  no 
compensating  arm 
jointed   to   any  fixed 


Section  of  Crosby's  Indicator. 


point,  as  in  other  indicators ;  that  the  pencil  is  located  close  to 
the  piston-rod,  instead  of  projecting  several  inches  to  one  side, 


256 


THE   engineer's  HANDY-BOOK. 


as  in  other  cases;  that  an  air-chamber  or  jacket  surrounds  the 
steam-cylinder  instead  of  a  steam-jacket,  as  in  other  instances; 
that  the  piston-rod  is  hollow  instead  of  solid,  and  that  it  is  solidly 
united  to  the  piston,  thus  requiring  no  joints  below  the  cap, 
which  obviates  the  possibility  of  corrosion  by  the  action  of  the 
steam  or  moisture;  that  there  is  no  link  or  connecting-bar  be- 
tween the  head  of  the  piston-rod  and  lever  to  cause  friction  or 
inaccuracy  of  motion ;  that  the  cylinder,  piston,  and  piston-rod 
are  automatically  oiled  by  a  self-lubricating  device,  thus  removing 
the  possibility  of  friction,  which  always  induces  error  in  the  re- 
cordings of  the  indicator,  thus  rendering  the  diagram  deceptive 
even  to  experts  ;  that,  wherever  possible,  every  joint  is  made  with 
steel  pivots  instead  of  journals,  as  is  the  case  in  other  instruments ; 
that  the  mechanism  for  adjusting  each  instrument  is  so  arranged 
that  it  may  be  used  either  left-  or  right-handed,  as  the  case  may  be, 
in  order  that  diagrams  may  be  taken  from  either  end  of  the  cyl- 
inder without  the  necessity  of  two  indicators ;  that  means  are 
provided  for  adjusting  the  distance  that  the  paper  shall  move 
towards  the  pencil,  so  that  a  hair-line  can  be  drawn  without  fric- 
tion ;  that  the  reduction  in  weight  in  the  piston  and  hollow  piston- 
rod  and  the  refinement  of  workmanship  in  the  levers  and  joints, 
render  the  reciprocating  parts  so  extremely  light  that  momentum 
and  friction  are  reduced  to  a  minimum ;  that  it  is  more  easily  ad- 
justed and  operated  than  any  other  instrument  of  the  kind  ever 
heretofore  invented,  thus  dispensing  with  the  necessity  of  experts, 
and  that  diagrams  may  be  taken  from  each  end  of  a  steam-cylin- 
der without  the  least  diflSculty,  even  by  engineers  of  ordinary  in- 
telligence and  limited  experience,  from  engines  running  at  the 
highest  practicable  piston  speed. 

They  ape  manufactured  by  the  Crosby  Steam  Gauge  and  Valve 
Co.,  Boston,  Mass. 

The  Thompson  Improved  Indicator. 
The  Thompson  Indicator,  see  page  251,  improved  and  patented 
by  J.  W.  Thompson,  of  Salem,  O.,  is  the  only  instrument  now  in 


THE    ENGlNEEll\s    fl  A  N  D  Y  -  H  (>  ()  K  . 


267 


use  that  can  be  used  on  very  high-speed  engines  with  success  ;  and 
it  works  equally  as  well  on  slowly  as  quickly  running  engines.  It 
will  give  correct  results  under  any  attainable  speed  of  an  engine 
or  locomotive. 

The  adoption  of  high-piston  speed  of  stationary  and  locomotive 
engines  has  created  a  demand  for  an  indicator  that  will  take  cards 
at  a  very  high  speed,  say  three  hundred  revolutions  per  minute, 
or  even  more. 

It  will  be  observed  that  Mr.  Thompson's  improvement  mainly 
consists  in  reducing  the  weight  of  the  parallel  motion,  by  lessening 
the  number  of  vibrating  pieces,  thereby  decreasing  the  tendency 
to  make  wavy  lines  in  both  steam  and  expansion.  ^  By  this  arrange- 
ment, the  instrument  is  lighter  and  more  compact, — qualities  which 
will  be  fully  appreciated  by  all  intelligent  engineers. 

The  Thompson  Indicator  has  taken  the  first  premium  wherever 
exhibited  in  competition  with  other  indicators. 

About  two  years  since,  the  United  States  Government  being 
desirous  of  ascertaining  which  of  the  various  patterns  of  indicators 
in  use  was  the  most  efficient,  with  a  view  to  its  adoption  as  the 
Standard  for  naval  service,  Engineer-in-Chief  Wm.  H.  Shock, 
U.  S.  N.,  Chief  of  the  Bureau  of  Steam  Engineering  of  the  Navy 
Department,  issued  an  order  directing  the  Commandant  of  the 
Boston  Navy  Yard  to  appoint  a  board  for  this  purpose.  The  board 
consisted  of  three  officers  of  the  Engineer  Corps,  who  reported 
unanimously  in  favor  of  the  Thompson  Indicator,  and  it  was  sub- 
sequently adopted  by  the  United  States  Navy  Department  as  the 
Standard  Indicator. 

The  Thompson  Indicator  is  also  in  use  by  all  the  principal 
Institutes  of  Technology  throughout  the  country. 

By  an  ingenious  device,  invented  by  Mr.  Thompson,  cards  can 
be  taken  with  this  instrument  at  a  pressure  as  high  as  five  hundred 
pounds  to  the  square  inch. 

The  Thompson  Indicator  is  manufactured  by  the  American 
Steam-Gauge  Company,  Boston,  Mass.,  who  have  been  eminently 
successful  in  the  manufacturing  of  first-class  instruments  for  nearly 
22*  R 


258 


THE   engineer's  HANDY-BOOK. 


thirty  years,  and  who,  seeing  the  superiority  of  the  Thompson  over 
any  other  make,  negotiated  with  Mr.  Thompson  for  the  sole  manu- 
facture and  sale  of  same.  The  cut  on  page  251  shows  the  indi- 
cator as  it  was  made  when  the  manufacturers  received  it  from  Mr. 
Thompson.  But  knowing  that  the  principle  of  the  Thompson  was 
far  superior  to  any  other  indicator  in  the  market,  and  being  desir- 
ous of  keeping  far  in  adVance  of  all  other  manufacturers  of  indi- 
cators, the  manufacturers  have  made  some  very  important  improve- 
ments in  the  indicator,  so  that  it  is  now  known  as  the  Thompson 
Improved  Indicator,  as  shown  by  the  following  cuts. 


The  Thompson  Improved  Indicator.      Section  of  the  Thompson  tm- 


The  important  improvements  consist  in  lightening  the  moving 
parts,  substituting  steel  screws  in  place  of  taper-pins,  using  a  very 
light  steel  link  instead  of  a  large  brass  one,  reducing  the  weight 
of  the  pencil-lever,  also  weight  of  square  in  trunk  of  piston  and 
lock-nut  on  end  of  spindle,  and  increasing  the  bearing  on  connec- 
ulon  of  parallel  m.oticn     By  shortening  the  length  and  reducjig 


proved  Indicator. 


THE   engineer's   II  ANDY- HOOK.  259 

the  actual  weight  of  the  paper  cylinder  just  one-half,  and  hy  short- 
ening the  bearing  on  spindle  so  that  it  now  carries  the  drum-spring 
nearer  the  base,  they  have  reduced  the  momentum  of  the  paper 
cylinder  to  a  very  small  amount.  All  of  these  improvements  have 
lessened  the  amount  of  friction,  which  was  heretofore  very  small, 
but  is  now  reduced  to  a  minimum,  and  the  Thompson  Improved 
Indicator  as  it  is  now  made  is  without  a  peer,  and  is  the  standard 
Indicator  in  Europe  and  this  country,  and  has  been  adopted  by  the 
most  eminent  engineers  in  both  countries. 

Some  of  the  advantages  of  Thompson's  Improved  Indicator  are : 
that  it  is  handsome  in  design,  and  convenient  and  simple  in  ar- 
rangement ;  that  cards  can  be  taken  at  a  pressure  as  high  as  500 
lbs.  to  the  square  inch  ;  that  they  are  easily  adjusted  and  operated  ; 
that  all  the  moving  parts  have  been  lightened,  which  is  a  con- 
sideration of  great  importance,  especially  for  engines  travelling  at 
a  high  rate  of  piston  speed ;  that  it  is  made  of  materials  carefiiUy 
selected  and  accurately  fitted,  thus  insuring  durability ;  and  that 
they  are  adapted  to  all  purposes  for  which  such  instruments  are 
employed. 

Every  Indicator  is  tested  at  the  works  by  being  attached  to  an 
engine  before  being  sent  out,  and  tried  under  different  pressures, 
which  insures  satisfaction  in  the  working  ;  so  that  it  is  sure  to  meet 
all  the  requirements  for  which  it  is  intended. 

Tabor's  Indicator. 

The  cuts  on  pages  260,  261,  represent  Tabor's  Steam-Enginp 
Indicator.  — As  will  be  observed,  its  most  striking  features  are  its 
parallel  motion  and  the  plainness  of  its  cylinder.  The  piston  has 
a  single  capillary  packing  groove,  and  its  whole  action  is  remark- 
ably nice.  The  springs,  both  as  to  range  and  general  structure, 
are  similar  to  those  in  the  Richards  and  Thompson  Indicator.  It 
will  be  noticed  that  the  piston-rod,  which  is  jointed  to  the  piston 
and  the  pencil-lever,  is  slotted ;  this  slot  is  curved,  and  works 
over  a  guide-roller  set  iu  the  cylinder-cap.    The  rear  end  of  the 


260 


THE   engineer's  HANDY-BOOK. 


pencil-lever  is  pivoted  to  the  radius  link.  The  slot-curve  is  that 
peculiar  curve  which  would  be  described  by  ihe>  guide-roller  aS  a 
scribing  point  while  the  pencil  is  being  moved  in  a  true  line; 
this,  it  is  claimed,  insures  a  correct  parallel  motion  to  the  pencil. 
The  guide-roller  is  journalled  in  a  free  collar  held  in  the  cylinder- 
cap,  which  allows 
all  the  moving  parts 
to  revolve  freely,  as 
the  pencil  is  brought 
in  contact  with  the 
paper. 

The  paper  drum 
revolves  on  a  steel 
spindle,  upon  which 
the  bottom  nut  is 
screwed;  the  nut 
inside  the  drum  is 
simply  a  milled  head 
firmly  screwed  on 
the  upper  end  of  the 
spindle.  The  recoil- 
spring  is  seated  in  a 
cup  on  the  bracket, 
the  outer  end  being 
fixed  to  it,  while  the 
inner  end  is  hooked 
Tabor's  Indicator.  by  the  hub  on  the 

drum-base.  A  stop- 
block  on  the  cup,  engaging  with  a  lug  in  the  drum-base,  forms  the 
stop  for  the  recoil  motion.  If  the  spindle  be  slacked  somewhat, 
the  drum-base  may  be  revolved  over  the  stop-block,  and  more  or 
less  tension  given  to  the  recoil-spring.  By  simply  unscrewing  the 
cylinder-cap,  the  whole  motion  work  may  be  removed  in  one 
piece.  The  pencil-lever,  piston-rod,  and  radius-link,  are  all  of  steel, 


THE   ENGINEER'S  HANDY-BOOK. 


261 


spring  tempered ;  the 
small  number  of 
moving  parts,  and 
their  lightness,  re- 
duce the  error  of 
momentum  that  ex- 
ists in  instruments 
of  heavier  parts, 
which  is  frequently 
a  source  of  uncer- 
tainty. The  whole 
instrument  is  very 
light,  the  design  sim- 
ple, and  the  work- 
manship neatly  done. 
It  is  claimed  that  the 
diagrams  produced 
are  very  good. 


Section  of  Tabor's  Indicator. 


Functions  of  the  Indicator. 

The  function  of  the  indicator  is  to  automatically  trace  out  on 
paper  a  diagram  that  will  graphically  represent  the  pressure  of 
the  steam  in  the  cylinder  of  the  engine  to  which  it  is  attached,  with 
all  its  variations  during  both  forward  and  return  strokes  of  the 
piston.  It  enables  those  who  use  or  have  charge  of  steam-engines, 
to  ascertain  the  condition  of  the  parts  of  the  engine  subject  to 
the  direct  action  of  the  steam,  and  to  what  advantage  the  steam 
is  applied;  whether  the  valves  are  properly  designed  and  ac- 
curately set,  and  if  the  steam-passages  or  ports  are  of  the  proper 
size  to  receive  and  discharge  the  steam  in  time  to  produce  the  best 
effect ;  what  pressure  of  steam  there  is  upon  the  piston  at  every 
position  in  the  cylinder,  as  w^ell  as  its  average  during  the  stroke; 
what  is  the  value  of  the  vacuum  acting  upon  the  piston  of  a  con- 
densing engine  in  all  its  positions  in  the  cylinder,  and  what  is  its 


262 


THE   ENGINEER'S  HANDY-BOOK. 


average ;  whether  the  exhaust  passages  from  the  cylinder  are 
sufficiently  large  to  give  free  exit  to  the  steani,  and,  if  not,  what 
percentage  of  power  is  lost  in  forcibly  expelling  it;  the  actual 
consumption  of  steam  in  giving  motion  to  the  engine,  and  also 
what  additional  steam  is  used  in  giving  motion  to  the  slrafting 
and  millwark,  the  paddle-wheel  or  screw-propeller ;  and  also  what 
power  is  required  to  move  the  machinery,  or  any  part  of  it. 

In  manufacturing  establishments  where  power  is  let  to  tenants 
it  will  show  how  much  is  consumed  by  each,  and  it  will  also  dem- 
onstrate the  degree  of  economy  in  using  steam  at  different  press- 
ures, the  benefits  of  expansion,  and  the  relative  efficiency  of 
different  kinds  of  expansion-gear. 

Indicator  cards  are  of  great  value,  as  they  demonstrate  the 
initial,  mean  effective,  and  terminal  pressures,  the  back  pressure, 
the  cushion,  whether  by  compression  or  lead ;  the  point  of  cut-off, 
and  the  relative  economy  of  different  engines,  aside  from  leakage 
and  condensation.  It  may  be  applied  not  only  to  steam-engines, 
but  to  those  driven  by  compressed  air,  or  any  vapor  or  fluid,  as 
w^ell  as  to  the  cylinders  of  air-pumps,  air-compressors,  blast-engines, 
etc.  The  diagram  produced  is  the  joint  production  of  two  move- 
ments, viz.,  a  vertical  movement  of  the  marking  point  due  to  the 
pressure  of  the  steam  acting  on  the  piston  of  the  instrument,  in 
opposition  to  the  force  of  a  spring  of  known  strength,  and  a  hor- 
izontal movement  of  the  paper,  as  the  drum,  on  which  it  is  placed, 
makes  partial  rotations  to  and  fro  coincident  with  the  movement 
of  the  piston.  Hence,  when  the  pencil  is  held  in  contact  with  the 
paper  during  one  revolution  of  the  engine,  both  will  arrive  at  the 
point  from  which  they  started  at  the  same  moment,  and  a  closed 
figure  will  be  the  result,  except  when  a  great  change  in  the  load 
and  pressure  occurs  during  the  stroke  in  which  the  diagram  was 
taken. 

The  value  of  indicator  diagrams  is  that  they  show  what  propor- 
tion of  the  boiler  pressure  is  contained  in  the  cylinder ;  how  early 
in  the  stroke  the  highest  pressure  is  reached  ;  how  well  it  is  main- 
tained ;  at  what  point  and  at  what  pressure  the  steam  is  cut  off; 


THE   ENGINEER'S    HANDY-BOOK.  263 

whether  it  is  cut  off  sharply,  or  in  what  degree  it  is  wire-drawn; 
at  what  point,  and  at  what  pressure  it  is  released;  whether  it  is 
freely  discharged,  or  what  proportion  of  it  (in  excess  of  the  atmos- 
phere or  the  vacuum  in  the  condenser,  according  as  the  engine  is 
condensing  or  non^condensing)  remains  to  exert  a  counter  or  back 
pressure ;  whether,  before  the  commencement  of  the  stroke,  there 
is  any  compression  of  the  vapor  remaining  in  the  cylinder,  and  if 
so,  at  what  point  in  the  stroke  it  commences,  and  to  how  high  a 
pressure  it  rises.  The  foregoing  particulars  can  only  be  learned 
by  observation,  though  a  scale,  corresponding  with  the  spring  used, 
is  needed  to  measure  the  pressures,  and  to  locate  the  exact  events 
in  the  stroke.  The  points  to  be  observed  in  estimating  diagrams 
are,  the  mean  or  average  pressure ;  the  total  mean,  or  the  mean 
effective  pressure ;  the  indicated  horse-power,  I.  H.  P.,  and  the 
theoretical  water  consumption.  The  indicator  shows  the  pressure 
at  each  and  every  point  in  the  stroke;  to  represent  this  faithfully 
is  its  sole  office.  The  causes  which  determine  the  form  of  the 
figure  must  be  determined  by  the  engineer. 

Technical  Terms  Used  in  Connection  with  the  Employ- 
ment of  the  Indicator, 

The  term  Adiabatic  literally  means  no  transmission.  As  applied 
to  an  expansion  curve,  it  means  that  it  correctly  represents  at  all 
points  the  pressure  due  both  to  the  volume  and  the  temperature, 
just  as  if  no  transmission  of  heat  to  or  from  it  had  taken  place. 

Admission. — This  term  is  applied  to  the  induction  of  the  steam 
into  the  cylinder  when  the  valve  opens  at  the  commencement  of 
the  stroke. 

The  term  Asymptote  means  a  line  which  approaches  nearer  and 
nearer  to  some  curve,  but  which,  though  infinitely  extended,  would 
never  meet  it.  The  clearance  and  vacuum  lines  of  a  diagram  are 
asymptotes  of  a  true  expansion  curve. 


264 


THE   engineer's  HANDY-BOOK. 


The  letter  B  at  the  end  of  a  diagram  means  that  that  end  was 
taken  from  the  bottom  end  of  the  cylinder. 

A.  B.  OP  Aba.  is  understood  to  stand  for  above  atmosphere,  and 
B.  A.  or  Bla.  below  atmosphere. 

The  term  Compression  is  a  term  used  to  express  the  distance 
through  which  the  piston  moves  in  the  cylinder  after  the  exhaust 
has  closed.  Compression  takes  place  between  the  piston  and  the 
cylinder-head  at  the  end  of  each  stroke;  and  the  distance  from  the 
end  of  the  cylinder  at  which  it  takes  place  depends  on  the  amount 
of  lap  on  the  valve. 

The  term  Cushion  means  the  resistance  offered  on  the  opposite 
side  of  the  piston  induced  by  the  steam  shut  up  in  the  cylinder. 

Cylinder  efficiency. — This  term  is  used  to  designate  the  amount 
of  work  performed  in  the  cylinder  of  a  steam-engine  for  a  given 
pressure. 

The  term  Clearance  is  used  to  express  the  extent  of  the  space 
which  exists  between  the  piston,  the  cylinder-head,  and  the  valve- 
face  at  each  end  of  the  stroke.    See  page  122. 

Displacement.  —  This  term  is  applied  to  the  cubic  contents,  or 
the  volume  of  water,  steam,  or  air  displaced  by  the  piston  during 
one  stroke.  It  may  be  found  by  multiplying  the  area  of  the  piston 
in  inches  by  its  stroke  in  inches.  The  product  will  be  its  displace- 
ment in  cubic  inches. 

Duty.  —  This  term  is  understood  by  engineers  to  mean  the  effi- 
ciency of  steam-engines,  or  the  number  of  pounds  that  an  engine 
is  capable  of  raising  one  foot  high  per  second  with  an  expenditure 
or  consumption  of  one  hundred  pounds  of  coal. 

The  term  Flexure  means  bending  or  curving.  The  point  of 
flexure  in  a  diagram  is  the  point  at  which  the  cut-off  closes  anc) 
the  expansion  curve  begins,  as  shown  at  C,  explanatory  diagram 


THE   engineer's  HANDY-BOOK. 


265 


No.  1,  page  291.  The  point  of  contrary  flexure  is  the  point  at 
which  the  line  changes  its  direction  by  curving  outwards  and 
afterwards  inwards,  as  shown  at  A,  on  diagram  on  page  291. 

H.  P.  cyl.  stands  for  high-pressure  cylinder.  ♦ 

H.  P.  means  horse-power,  which,  when  applied  to  the  steam- 
engine,  means  33,000  lbs.  raised  one  foot  high  ;  or  150  lbs.  raised 
220  feet  high  ;  or  550  lbs.  raised  one  foot  high  in  one  second. 

The  term  Hyperbola  means  a  plane  figure  which  is  formed  by 
cutting  a  portion  from  a  cone  by  a  plane,  parallel  to  its  axis  or  to 
any  plane  within  the  cone,  which  passes  through  the  cone's  vertex. 
The  curve  of  the  hyperbola  is  such,  that  the  difference  between 
the  distances  of  any  point  in  it  from  two  given  points  is  always 
equal  to  a  given  right  line. 

The  term  Isothermal  means  uniform  or  same  temperature.  As 
applied  to  an  expansion  curve,  it  means  that  such  a  curve  repre- 
sents correctly  the  expansion  or  compression  of  the  steam  when 
the  temperature  is  uniform. 

•    L.  P.  cyl.  means  low-pressure  cylinder. 

The  term  Ordinates  means  the  vertical  lines  drawn  across  dia- 
grams to  facilitate  the  calculation  of  their  power.  See  diagram 
on  page  291. 

The  term  Parallelism  is  generally  employed,  where  two  or  more 
straight  lines  may  be  extended  indefinitely,  without  any  tendency 
to  approach  or  diverge  from  one  another.  See  atmospheric  and 
vacuum  lines  on  indicator  diao^rams. 

Release.  —  This  term  is  understood  to  mean  exhaust.  Besid- 
uary  exhaust  is  that  which  follows  the  first  release  of  the  terminal 
pressure.  The  term  negative  exhaust  is  sometimes  used,  though 
not  generally  understood  in  its  literal  sense.  It  means  compres- 
sion or  cushion,  and  absolutely  amounts  to  the  same  thing,  as  it  Ls 
23 


266  THE   ENGINEEP/S  HANDY-BOOK. 

merely  an  early  product  of  the  exhaust,  for  the  purpose  of  retain- 
ing a  portion  of  steam  in  the  cylinder  as  the  crank  approaches 
the  centre  of  the  stroke. 

Rev.  or  Rev's  is  understood  to  mean  revolutions  per  minute, 
though  rspm  is  sometimes  used. 

I.  H.  P.  means  indicated  horse-power.  It  means  the  number 
of  H.  P.  of  energy  shown  by  the  diagram  of  an  engine,  as  found 
by  multiplying  together  the  area  of  the  piston  in  square  inches, 
its  speed  in  feet  per  minute,  and  the  mean  effective  pressure  shown, 
and  dividing  the  product  by  33,000. 

N.  H.  P.  means  nett  horse -power,  which  is  the  I.  H.  P.  minus 
the  friction  of  the  engine.  ^ 

The  term  Initial  pressure  is  generally  understood  to  mean  the 
pressure  represented  in  the  cylinder  between  the  opening  of  the 
steam-valve  and  the  closing  of  the  cut-off.  More  properly  speak- 
ing, it  is  the  pressure  represented  in  the  cylinder  at  the  commence- 
ment of  the  stroke,  as  the  pressure  frequently  falls  considerably 
before  the  closing  of  the  cut-off. 

M.  E.  P.  means  mean  effective  pressure.  It  is  simply  the 
amount  by  which  the  average  impelling  pressure  exceeds  the 
average  resisting  or  counter-pressure.  The  M.  E.  P.  on  the  piston 
of  a  steam-engine  is  the  measure  or  exponent  of  the  work  per- 
formed. 

The  term  Terminal  pressure  means  the  pressure  at  which  the 
steam  is  exhausted  from  the  cylinder,  and  may  be  said  to  be  the 
exponent  of  the  consumption  of  water  by  the  engine. 

The  term  Pipe  diagram  is  applied  to  diagrams  taken  from  the 
steam-pipe  for  the  purpose  of  determining  how  much  of  the  press- 
ure of  the  steam  in  the  pipe  is  lost  in  passing  through  the  steam- 
ports  to  the  cylinder. 


THE   ENGINEER'S  HANI)Y-BOOK. 


267 


The  term  Scale  means  the  number  of  pounds  of  steam  per 
square  inch  (acting  on  the  piston  of  a?i  engine)  represented  by 
each  inch  of  vertical  height  on  the  diagram.  Thus  a  40  lb.  scale 
means  that  each  inch  on  the  diagram  represents  40  lbs.  of  steam 
per  square  inch,  and  so  on. 

The  term  Spring  means  the  spring  which  is  employed  on  the 
piston  of  the  instrument,  in  order  to  resist  the  pressure  of  the 
steam  and  the  vacuum.  The  following  table  will  give  the  limit 
of  presi5ine  in  the  cylinder  to  which  each  spring  may  be  subjected. 
The  length  of  each  spring  given  in  the  third  column  is  such  that 
each  of  them  would  be  extended  (when  subjected  to  a  perfect 
vacuum)  to  a  length  of  inches,  which  is  the  approximate 
length  which  would  cari-y  the  pencil  to  the  lower  limit  of  the 
range  of  movement  above  given. 


Scale  of 
Spring. 

Limit  of 
Cylinder- 
Pressure 
ABOVE  At- 
mosphere. 

Length  of  Spring. 

 — 

15  lbs.  per  in. 

25  lbs. 

2-192 

ins.  —  nearly  2\ 

ins. 

20  " 

38  " 

2-255 

"   —a  little  above  2i 

30  " 

64  " 

2-315 

a                   <<             <<       O  3 

— 

or  nearer  2fQ 

u 

40  " 

90  " 

2-345 

"   =  nearly  2-/o 

(( 

60  " 

143  " 

2-376 

"   =  a  little  over  2| 

a 

"80  " 

195 

2-391 

"   =  a  little  above  2| 

n 

To  find  the  corresponding  limit  for  grades  not  given,  multiply 
the  total  range  of  movement,  2  625  inches,  by  the  scale  of  the 
spring,  and  deduct  the  pressure  of  the  atmosphere. 

Example. —  Suppose  it  is  desired  to  find  the  limit  of  pressure  for 
a  50  lb.  spring :  50  X  2-625  — 14-7  =  116-55. 


The  term  String,  as  used  in  these  pages,  means  the  aggregate 
length  of  the  ordinates  of  an  indicator  diagram. 


268 


THE   ENGINEER'S  HANDY-BOOK. 


The  letter  T  on  a  diagram  denotes  that  that  end  was  taken  from 
the  top  end  of  a  cylinder* 

The  term  Undulating  means  rising  and  falling,  wavy.  See 
dotted  line  on  diagram  No.  16,  page  303. 

Wire-drawing, —  This  term  is  applied  to  the  common  method 
of  regulating  the  flow  of  steam  from  the  boiler  to  the  cylinder, 
by  throttling  or  forcing  the  steam  to  ooze  through  some  small  or 
intricate  device,  such  as  the  governor-valve,  thus  tending  to  destroy 
its  elastic  force. 

The  term  Zero,  when  applied  to  indicator  diagrams,  means  a 
vacuum. 

How  to  Attach  the  Indicator. 

Since  it  is  of  the  first  importance  that  the  diagram  should  be 
correct,  both  as  to  its  vertical  and  horizontal  measurements,  too 
much  care  cannot  be  taken  in  making  the  attachments.  The  best 
method  of  attaching  the  indicator  to  the  engine  is  to  drill  and 
tap  into  the  cylinder  directly  opposite  the  ports.  When  practi-* 
cable,  the  holes  should  be  located  exactly  at  the  centre  of  the 
clearance,  or  the  space  between  the  piston  and  the  cylinder,  when 
the  crank  is  at  the  dead-centre;  since,  if  the  holes  are  bored  in 
any  part  of  the  cylinder  which  is  travelled  over  by  the  piston,  the 
communication  with  the  indicator  will  be  closed  at  that  point  in 
each  stroke.  Care  must  also  be  taken  that  they  are  not  too  close 
to  the  cylinder-heads,  as  the  projecting  parts  of  the  latter  may 
interfere  with  the  free  flow  of  the  steam  between  the  cylinder  and 
the  indicator.  But  if  such  a  difficulty  should  arise,  recesses  must 
be  cut  in  the  cylinder-heads,  in  order  to  establish  the  communi- 
cation. If  the  heads  can  be  removed  for  the  purpose  of  locating  the 
holes,  it  is  always  best  to  do  so,  as  their  exact  location  can  be  de- 
termined with  perfect  accuracy. 

If  circumstances  will  not  admit  of  the  holes  being  drilled  into 
the  clearance,  they  may  be  put  in  the  heads ;  and,  if  it  is  not  in- 


THE   ENGINEER'S  ITANDY-BOOK. 


269 


tended  to  place  the  instrument  in  connection  with  both  ends  of 
the  cylinder  at  the  same  time,  this  location  is  preferable.  It  is 
claimed  by  many  engineers  that  reliable  diagrams  cannot  be  ol)- 
tained,  when  the  pressure  has  to  be  transmitted  through  a  long 
pipe,  as  is  the  case  when  the  instrument  is  connected  to  both  ends 
of  the  cylinder.  But  it  has  been  shown  by  experiment,  that  if 
the  cylinder  is  tapped  instead  of  the  heads,  thereby  using  the 
shortest  pipe,  and  the  stop-cocks  are  placed  as  near  as  possible  to 
the  instrument,  the  difference  between  diagrams  so  taken,  and 
those  taken  from  a  direct  attachment,  is  not  always  noticeable. 
If,  instead  of  two  stop-cocks,  one  on  each  side  of  the  instrument,  a 
three  way  cock  be  placed  under  it,  which  will  allow  steam  to  be 
admitted  from  either  end  through  the  same  plug,  the  difference 
can  hardly  be  detected.  If  no  such  cock  can  be  had,  straight  way- 
cocks  of  ample  aperture,  placed  as  close  to  the  L  or  T,  to  which 
the  instrument  is  attached,  as  possible,  will  give  sufficiently  satis- 
factory results  for  all  ordinary  purposes.  When,  however,  it  is 
decided  to  take  the  diagrams  separately,  two  cocks  become  neces- 
sary, and  the  card  must  also  have  tw^o  loops  or  hooks,  as  far  apart 
as  the  two  positions  which  the  instrument  is  to  occupy.  Then  it 
may  be  quickly  shifted  from  end  to  end  as  desired.  If  tw^o  in- 
struments are  attached  to  an  engine,  diagrams  may  be  taken 
simultaneously  from  both  ends ;  but,  while  such  an  arrangement 
obviates  the  difficulty  of  equalizing  the  events  of  the  two  ends 
with  one  instrument,  it  is  open  to  the  objection  that,  if  there  is  any 
difference  in  the  action  of  the  two  instruments,  or  in  the  strength 
of  their  springs,  this  circumstance  will  interfere  with  the  com- 
parison. 

Motion  of  the  Paper  Drum. 

Owing  to  the  almost  endless  variety  of  engines,  their  peculi- 
arities of  design,  etc.,  it  is  impossible  to  give  very  definite  instruc- 
tions which  will  be  applicable  to  all  cases.  But  it  must  be  borne 
in  mind,  that  the  motion  of  the  paper  drum  must  be  coincident 
with  that  of  the  piston  in  respect  to  its  times  of  stopping  and 
23* 


270 


THE  engine^:r's  handy-book. 


starting,  and  be  a  miniature  reproduction  of  it  in  all  other  re- 
spects ;  or,  in  other  words,  equal  piston  movements  must  be  rep- 
resented by  equal  movements  of  the  paper  throughout  the  whole 
stroke.  To  whatever  the  cord  may  be  attached,  whether  to  a  tem- 
porary wooden  pendulum  fastened  by  a  screw  to  a  post,  or  to  the 
beam  of  a  beam-engine,  it  (the  cord)  must  be  at  right  angles  to  a 
line  between  its  point  of  attachment  and  the  pivot  of  the  beam  or 
pendulum  to  which  it  is  attached,  when  the  piston  is  in  the  middle 
of  its  stroke.  For  instance,  suppose  the  engine  to  be  horizontal, 
and  that  a  wooden  pendulum  is  attached  to  a  light  post  set  up  by 
or  on  the  engine,  or  some  other  convenient  object,  or  is  suspended 
from  a  joist,  the  lower  end  being  connected  to  the  cross-head,  and 
that  the  point  on  the  pendulum  where  the  motion  is  sufficiently 
reduced  for  the  paper  drum  is  higher  than  the  instrument,  so  that 
the  cord  must  incline  downward.  In  such  a  case,  unless  a  carry- 
ing pulley  is  used  to  deflect  it  to  a  horizontal  direction,  or  unless 
the  point  of  attachment  for  the  cord  is  moved  as  many  degrees 
from  the  centre  line  of  the  pendulum  as  the  cord  inclines  down- 
wards, the  movement  of  the  pendulum  will  be  too  fast  at  one  end 
of  its  travel,  and  too  slow  at  the  other,  and  the  diagram  will  be 
distorted.  The  effects  of  such  distortion  will  be  to  cause  the  ends 
to  appear  unequal  when  they  are  not  so,  or  else  to  conceal  or  ex- 
aggerate inequalities  where  they  really  exist. 

The  length  of  the  pendulum  may  be  from  one  and  a  half  times 
to  twice  the  length  of  the  stroke  or  more.  If  too  short,  the  ends 
of  the  diagram  will  be  distorted,  unless  the  connection  between  it 
and  the  cross-head  is  sufficiently  long.  The  pendulum  may  be 
attached  to  some  object  at  the  side  of  the  engine,  so  that  it  may 
vibrate  in  a  horizontal  plane. 

A  good  substitute  for  a  pendulum  consists  of  a  drum  about  six 
inches  in  diameter,  more  or  less,  on  the  axis  of  which  is  another 
drum,  the  diameter  of  which  requires  to  be  as  much  less  than  the 
other  as  the  movement  of  the  paper  is  less  than  the  travel  of  the 
piston.  If  the  drum  is  mounted  in  a  convenient  position,  and  a 
cord  from  the  large  part  is  attached  to  the  cross-head,  and  another 


THE   engineer's  HANDY-ROOK. 


271 


from  the  small  part  to  the  indicator,  a  spring  in  the  large  drum 
keeps  its  cord  taut,  just  as  the  spring  in  the  drum  of  the  in- 
dicator keeps  its  cord  taut. 

When  two  instruments  (right  and  left),  are  used,  it  is  best  to 
fix  a  sliding-bar  alongside  of  them  having  the  proper  motion, 
carrying  pins  to  which  the  cords  are  attached,  these  pins  being 
placed  between  the  two  instruments  so  that  the  cord  of  each  may 
pull  towards  the  other,  and  the  movement  of  the  piston  from 
either  end  of  the  cylinder  may  pull  the  cord  of  the  instrument 
attached  to  that  end,  in  which  case  the  upper  line  of  each  dia- 
gram will  be  drawn  while  the  cord  is  being  pulled.  But  no  per- 
ceptible advantage  in  the  way  of  accuracy  need  be  expected  from 
this  arrangement,  though  it  is  a  very  convenient  one  where  a  large 
number  of  diagrams  are  to  be  taken. 

Analysis  of  diagrams. — All  the  various  particulars  which  may 
be  learned  from  the  indicator  diagram  may  be  classed  under  three 
heads. 

1.  Those  relating  to  the  condition  of  the  engine,  such  as  its 
construction,  adjustment,  etc. 

2.  The  mean  or  average  pressure  exerted  on  the  piston  as  an 
element  in  calculating  the  indicated  horse-power,  I.  H.  P. 

3.  The  theoretical  rate  of  water  consumption. 

Here  it  is  necessary  to  explain  the  terms  used  hereafter  to  des- 
ignate the  various  parts  of  the  diagram. 

In  diagram  No.  1,  A  A  shows  the  atmospheric  line  which  is 
drawn  when  both  sides  of  the  piston  of  the  indicator  are  exposed 
to  the  atmosphere.  When  tracing  such  a  diagram  it  is  preferable 
to  pull  the  cord  by  hand,  in  order  to  make  the  atmospheric  line 
longer  than  the  diagram ;  J5  C  is  called  the  steam  line.  It  is 
formed  while  steam  is  entering  the  cylinder.  C  is  the  point  of 
cut-off.  It  cannot  always  be  located  exactly  by  inspection,  as  the 
closure  of  the  part  is  generally  sufficiently  gradual  to  cause  con- 
siderable fall  of  pressure  before  the  port  is  entirely  closed.  In 
general,  it  may  be  located  at  the  point  where  tlie  outline  of  the 
figure  ceases  to  be  convex  and  commences  to  be  concave.    C 1) 


272         THE  engineer's  handy-book. 

is  the  expansion  line  or  curve.  D  is  the  point  of  exhaust,  which, 
like  that  of  the  cut-off,  may  be  located  at  the  point  of  contrary 
flexure,  or  that  point  where  the  expansion  line  begins  to  change 
the  direction  of  its  curvature.  D  E  is  the  exhaust  line.  It  com- 
mences at  the  point  of  exhaust,  and  may  be  considered  as  ter- 
minating at  the  end  of  the  stroke,  (though,  strictly  speaking,  it 
does  not  terminate  till  the  exhaust  port  closes  at  F.)  E  F  is 
termed  the  counter-  or  back-pressure  line,  and  by  some  the  vac- 
uum or  exhaust  line ;  but  the  former  terms  are  more  appropri- 
ate, as  they  are  applicable  to  all  diagrams,  whether  from  condens- 
ing or  non-condensing  engines.  In  the  diagrams  of  non-con- 
densing engines  it  is  above  the  atmospheric  line,  A  A  ;  while 
in  condensing  engines  it  is  below ;  but  in  both  cases  it  rep- 
resents some  counter-pressure,  since  a  perfect  vacuum  is  unat- 
tainable. F  is  the  point  of  exhaust-closure.  Its  exact  loca- 
tion cannot  be  so  readily  determined  as  the  points  C  and  D, 
as,  although  like  the  former,  it  is  anticipated  somewhat  by  a 
change  of  pressure,  it  is  not  marked  by  any  change  in  the  direc- 
tion of  the  curvature  of  the  line.  In  perfectly  working  engines 
it  may  be  located  geometrically,  but  it  is  seldom  necessary  to  do 
so,  since  for  all  practical  purposes  it  is  sufficient  to  know  w^here 
the  change  of  pressure  due  to  the  closing  of  the  exhaust  begins, 
and  its  final  result.  F  G  is  the  compression  curve,  and  G  £  is 
the  admission  line.  These  constitute  all  the  lines  which  belong 
to  the  diagram  proper,  and  all  that  are  produced  by  the  instru- 
ment. 

For  certain  purposes  the  vacuum  line  V  F,  and  the  clearance 
Vine  H  diagram  No.  1,  are  drawn,  the  former  parallel  to  the 
atmospheric  line,  and  at  such  a  distance  below  it  as  will  repre- 
sent, according  to  the  scale  used,  the  pressure  of  the  atmosphere 
as  it  was,  or  was  supposed  to  be,  at  the  time  and  place  at  which 
the  diagram  was  taken.  For  this  purpose  it  is  usual,  when  great 
accuracy  is  desired,  to  consult  a  barometer  at  the  time,  and 
record  its  reading  on  the  card;  but,  in  the  absence  of  a  barom- 
eter, it  is  usual  to  assume  the  pressure  at  14*7  lbs.  per  square 


THE  pjnginej:k^s  handy-hook. 


273 


inch,  which  is  the  average  at  sea  level ;  but,  since  the  pressure 
diminishes  at  the  rate  of  j\  lb.  for  each  189  feet  of  elevation, 
allowance  should  be  made  for  the  known  or  estimated  eleva- 
tion of  the  locality.  It  should  also  be  remembered  that  the 
pressure  will  vary  nearly  ^  lb.,  and  sometimes  more,  from  changes 
in  the  weather. 

The  clearance  line  HHj  diagram  No.  I,  is  drawn  perpendicular 
to  the  atmospheric  and  vacuum  lines,  and  at  such  a  distance  from 
the  induction  end  of  the  diagram,  that  the  space  between  them 
will  bear  the  same  proportion  to  the  whole  length  of  the  latter 
as  the  whole  volume  of  clearance  bears  to  the  piston  displace- 
ment. When  the  amount  of  clearance  is  unknown,  and  it  is  not 
practicable  either  to  calculate  it  or  measure  it  by  filling  the  space 
with  water,  it  must  be  approximated  as  near  as  possible  from  the 
known  clearance  of  engines  of  similar  construction.  The  largest 
clearance  will  be  generally  found  in  the  smaller  sized  engines  of 
the  ordinary  single  slide-valve  type.  Five  such  engines  tested  at 
the  Cincinnati  Industrial  Exposition  of  1875,  had  the  following 
amounts  9,  9^,  10,  11^,  and  12  per  cent,  of  the  cubic  contents  of 
the  cylinder.  Next  to  these  will  be  the  larger  sizes  of  the  same 
type,  in  which  the  clearance  will  range  from  6  to  10  per  cent. 
When  two  slide-valves  are  used  with  short,  direct  ports,  but  ex- 
hausting under  the  valves,  the  clearance  will  average  from  3  to  6 
per  cent.,  according  to  the  proportionate  length  of  the  stroke,  the 
longest  strokes  having  the  smallest  per  cent.  Corliss  engines,  in 
which  the  stroke  is  about  three  times  the  bore,  have  about  3  per 
cent.  The  least  amount  of  clearance  is  obtained  from  valves  de- 
signed to  exhaust  at  both  ends  of  the  cylinder,  instead  of  in  the 
centre,  as  in  the  case  of  the  ordinary  single  slide-valve.  By  such 
an  arrangement  of  the  steam-  and  exhaust-valves,  the  clearance 
has  in  many  instances  been  reduced  to  1|  per  cent.  The  clearance 
in  poppet-valve  engines  is  more  difficult  to  calculate  than  in  slide- 
valve  engines;  but,  as  a  general  thing,  it  does  not  exceed  5  per  cent. 
It  should  be  measured  with  water,  when  it  is  desirable  to  ascertain 
accurately  the  cubic  contents  of  the  clearance.    In  poppet-valve 

S 


274         THE  engineer's  handy-book. 


engines  the  cut-off  and  other  events  are  independent  and  adjust- 
able; consequently,  diagrams  taken  from  this  class  of  engines  are 
free  from  the  limitations  attending  those  taken  from  slide-valve, 
because  advantage  is  frequently  taken  of  their  freedom  of  adjust- 
ment to  give  an  earlier  cut-off,  or  a  later  depression  than  is  usually 
adopted  with  slide-valve  engines.  In  all  such  cases  the  diagram 
will  faithfully  state  the  fact. 

The  Most  Accurate  Methods  of  Testing  the  Adjustments. 

The  conditions  which  are  mainly  instrumental  in  determining 
the  conformation  of  the  diagram  are  the  valves  and  valve-gear, 
the  length  and  capacity  of  the  steam-  and  exhaust-pipes  and 
ports,  the  design  of  the  governor-valve,  the  condition  of  the 
valves  and  piston  as  to  leakage,  the  amount  of  clearance,  the 
speed  of  the  piston,  etc.  The  engineer  may  be  called  upon  to 
analyze  a  diagram  with  reference  to  all  the  above  conditions,  or 
only  to  accidental  derangements.  In  the  first  place,  he  must  com- 
pare the  diagram  with  one  of  the  best  form  which  can  be  pro- 
duced in  practice  from  the  class  of  engines  to  which  the  one  in 
question  belongs ;  in  the  second  case,  he  must  discriminate  between 
such  defects  as  are  due  to  accidental  derangements  and  those  that 
are  due  to  design  and  construction,  which  cannot  be  remedied 
without  the  substitution  of  new  parts.  Suppose  the  engine  to  be 
of  the  throttling  kind,  of  the  best  attainable  construction  and 
adjustment,  its  diagram  should  possess  the  following  general 
features : 

1.  The  initial  pressure  at  jB,  diagram  No.  1,  should  be  as  high 
at  least  as  any  subsequent  pressure;  and  if  the  engine  is  not 
driving  its  maximum  load,  and  the  steam  is  in  consequence  more 
or  less  throttled,  the  pressure  should  begin  to  fall  at  and  con- 
tinue to  do  so  at  a  tolerably  uniform  rate,  until  the  point  of  cut- 
off, C,  is  reached. 

2.  The  cut-off,  when  obtained  by  means  of  lap  in  the  slide- 
valve,  cannot,  as  a  general  rule,  take  place  with  advantage  earlier 


THE   engineer's  HANDY-BOOK. 


275 


Richards*  Parallel  Motion  Indicator. 


276         THE  engineer's  handy-book. 

in  the  stroke  than  about  f ,  as  the  angular  advance  necessary  to 
give  any  earlier  cut-off  would  involve  a  too  early  exhaust  and  com- 
pression. 

3.  From  the  cut-off,  C,  to  the  release,  Z>,  is  the  expansion 
curve.  Assuming  the  applicability  of  the  Mariotte  law  to  expand- 
ing steam,  the  shape  of  the  expansion  curve,  C  E,  should  be  such 
that,  if  the  distance  from  any  point  in  it  to  the  clearance  line,  H 
H,  taken  on  a  line  parallel  with  the  atmospheric  line,  be  multiplied 
by  the  distance  from  the  same  point  to  the  vacuum  line  measured 
vertically,  the  product  will  be  the  same  for  all  points  in  the  curve. 
Hence,  if  at  the  commencement  of  the  curve,  the  two  measure- 
ments are  multiplied  together,  and  the  product  divided  by  the 
distance  from  the  clearance  line  to  any  other  point,  the  quotient' 
will  be  the  distance  of  that  point  from  the  vacuum  line,  or  the 
pressure  at  that  point,  if  the  pressure  scale  is  used  for  the  measure- 
ments. 

4.  The  release  at  Z>  will  take  place  earlier  or  later,  according  to 
the  amount  of  lap,  both  steam  and  exhaust,  that  is  introduced. 
The  steam-lap  affects  it  indirectly,  as,  the  greater  it  is,  the  greater 
the  angular  advance  necessary  to  maintain  the  proper  lead.  Lap 
on  the  exhaust  side  affects  it  directly  without  change  in  the  angu- 
lar advance,  by  opening  the  port  so  much  later,  and  consequently 
closing  it  so  much  earlier.  The  requirements  of  perfect  working 
are,  that  it  shall  be  early  enough  to  release  the  piston  of  all  undue 
back  pressure  before  much  of  the  return  stroke  is  made,  and  late 
enough  not  to  materially  diminish  the  power  of  the  engine.  The 
conformation  of  diagram  No.  1,  page  291,  shows  about  as  early 
an  exhaust  as  is  admissible,  because  little  or  nothing  would  be 
gained  by  a  later  one,  as  the  steam  is  not  thoroughly  exhausted 
until  the  piston  has  moved  a  short  distance  on  its  return  stroke ; 
and,  while  a  later  release  would  add  a  little  to  the  average  forward 
pressure,  it  would  also  increase  the  back  pressure.  Besides,  a  later 
release  would  involve  either  a  later  cut-off  or  an  earlier  compres- 
sion ;  and,  although  the  general  practice  is  to  place  all  these  events 
later  than  is  shown  on  the  diagram,  such  practice  is  not  calculated 


THE   engineer's    HANDY- BO  OK. 


277 


to  realize  the  best  possible  steam  economy  with  that  class  of  en- 
gines. 

5.  The  back-pressure  line,  EF,  should  coincide  with  the  atmos- 
phere, or  nearly  so,  in  non-condensing  engines  and  with  the 
pressure  shown  by  the  vacuum-gauge  in  condensing  engines. 
When  it  is  in  excess  in  either  case,  it  indicates  insufficient  capac- 
ity in  the  exhaust-ports  or  pipes,  or  both. 

6.  The  compression  curve,  F  G,  owes  its  form  to  the  same  laws 
that  govern  the  expansion  curve,  and  its  degree  of  conformity  to 
theory  may  be  tested  by  the  same  methods.  The  only  differences 
between  the  two  are  in  the  quantities  of  steam  evolved  in  their 
production,  and  the  order  of  their  formation ;  the  ending  of  one 
corresponding  to  the  beginning  of  the  other.  As  to  the  amount 
required  to  satisfy  the  best  conditions,  some  difference  of  opinion 
exists.  It  is  ascertained  that  a  certain  amount  is  advantageous, 
as  a  means  of  arresting  the  momentum  of  the  reciprocating  parts, 
while  changing  the  direction  of  the  force  on  the  crank-pin  in  a 
more  gentle  and  quiet  manner,  than  would  be  done  by  the  admis- 
sion of  steam  as  an  opposing  force.  If  the  compression,  or,  more 
properly  speaking,  the  cushion  has  fulfilled  its  functions,  the  in- 
duction will  find  the  parts  already  prepared  for  the  shock,  and 
prevent  a  jar  or  thump.  The  maximum  pressure  reached  by  the 
cushion  should  never  be  greater  than  the  average  initial  pressure; 
but  within  this  limit  considerable  latitude  exists,  as,  while  it  dimin- 
ishes the  power  of  the  engine,  it  lessens  the  consumption  of  steam. 
The  less  the  exhaust-lap,  the  earlier  the  exhaust  will  take  place, 
and  the  later  the  compression,  and  vice  versa. 

7.  The  lead  line,  G  B,  need  not  conform  to  any  arbitrary 
standard.  It  satisfies  the  eye  of  the  engineer  best  when  it  is  ver- 
tical, or  nearly  so ;  but  it  may  lean  slightly  inwards,  indicating 
deficiency  of  lead,  or  outwards,  indicating  excess,  without  affecting 
the  economy  of  the  engine,  and  in  most  cases  without  sensibly 
affecting  the  smoothness  of  its  running.  In  many  cases  the  com- 
mencement of  the  lead  line  proper  cannot  be  exactly  located ;  but 
engines  always  run  best  when  the  compression  and  lead  lines  join 

24 


278 


THE   engineer's  HANDY-BOOK. 


each  other  with  an  easy  curve.  When  a  single  slide-valve  is  used, 
both  the  steam-  and  exhaust-lap  must  be  provided  for  in  its  con- 
struction, and  cannot  be  subsequently  changed  without  a  change 
of  proportion.  But  since  it  is  not  the  absolute  amount  of  lap,  but 
its  amount  relatively  to  the  travel  of  the  valve,  which  determines 
its  influence,  it  follows  that,  by  reducing  the  travel,  the  lap  both 
steam  and  exhaust  will  be  virtually  increased,  and  vice  versd. 
Any  change  of  travel  must  be  accompanied  by  such  change  of 
angular  advance  as  will  maintain  the  proper  lead.  The  adjust- 
ment of  the  cut-off*  by  the  link-motion  of  the  locomotive  is  an 
instance  of  such  change  of  travel  and  angular  advance. 

In  the  foregoing  description  all  the  capital  letters  refer  to  dia- 
gram No.  1,  on  page  291. 

When  two  slide-valves  are  used,  each  performing  the  functions 
of  induction  and  exhaust  at  its  own  end  of  the  cylinder,  the  steam- 
lap  may  be  increased  by  setting  them  farther  apart,  and  dimin- 
ished by  contracting  their  connection  ;  but  in  such  cases  steam-lap 
is  obtained  at  the  expense  of  the  exhaust-lap,  and  vice  versd. 
Having  learned  from  an  engine  embodying  correct  construction 
and  performance  the  general  features  which  should  characterize 
a  diagram,  the  engineer  will  have  no  difficulty  in  recognizing 
defects  as  well  as  deviations  from  diagram  No.  1,  on  page  291. 
These  conditions  should  be  understood  before  the  slide-valve, 
throttling  engine  diagram  can  be  intelligently  criticised. 

Diagrams  taken  from  Automatic  Cut-Off  Engines. 

The  points  of  difference  between  diagrams  from  automatic 
eut-off*  engines  and  those  from  slide-valve  engines  will  be  mainly 
found  in  the  steam  lines,  the  points  of  cut-off",  and  the  expansion 
^jurve.  When  the  automatic  cut-off*  engine  is  worked  in  accord- 
ance with  the  theory  of  its  operation,  the  steam  is  never  throttled 
for  the  purpose  of  regulating  the  speed,  but  is  admitted  freely  to 
the  valves,  the  speed  being  regulated  solely  by  means  of  variations 
in  the  point  of  cut-off*.    Hence,  the  steam  line  should  indicate  a 


THE    engineer's  HANDY-BOOK. 


279 


pressure  equal  to  that  in  the  boiler,  whatever  the  load  may  be, 
and  would  undoubtedly  do  so,  if  the  proportions  were  good  and 
the  valve-gear  in  perfect  order.  The  necessary  difference,  then, 
between  the  throttling  and  automatic  cut-off  engine  diagrams, 
may  be  thus  stated.  In  the  former,  the  height  of  the  steam  line 
varies  with  the  load,  the  length  remaining  the  same ;  in  the 
latter,  the  length  of  the  steam  line  varies  with  the  load  and 
pressure,  the  height  remaining  always  approximately  that  of  the 
boiler  pressure. 

The  theoretical  diagram. — From  what  has  been  said  in  the 
foregoing  paragraphs,  it  is  clear  that  a  theoretical  diagram  may 
be  constructed,  representing  perfect  performance  on  the  automatic 
cut-off  principle,  which  cannot  be  done  in  the  other  case,  as  the 
height  and  conformation  of  the  steam  line  depends  on  conditions 
too  numerous  and  complex  for  analysis.  Thus,  with  a  given 
boiler-pressure  for  a  steam  line,  a  straight  horizontal  line  may  be 
drawn,  corresponding  with  that  pressure,  and,  from  a  given  point 
of  cut-off,  an  expansion  curve  may  be  drawn  having  the  properties 
already  described,  and  reaching  to  the  end  of  the  stroke.  If  the 
remaining  terminal  pressure  is  greater  or  less  than  the  counter- 
pressure,  a  vertical  line  extending  upwards  or  downwards  to  the 
height  required  by  the  counter-pressure  will  represent  a  perfect 
exhaust  line.  Then,  for  the  return  stroke,  a  line  coincident  with 
the  atmosphere  or  a  perfect  vacuum,  according  as  the  engine  is 
non-condensing  or  condensing,  will  represent  the  counter-pressure, 
and  a  vertical  line  up  to  the  beginning  of  the  steam  line  will 
represent  the  admission  line  and  complete  the  figure. 

If  a  compression  curve  is  desired,  it  may  be  drawn  through  the 
assumed  or  actual  point  of  exhaust-closure  on  the  counter-pressure 
line,  but  such  a  curve  cannot  originate  from  a  perfect  vacuum. 
Hence,  when  the  diagram  is  from  a  condensing  engine,  and  the 
actual  compression  curve  is  to  be  tested  by  a  theoretical  one,  the 
latter  must  be  based  on  the  actual  counter-pressure  present  at  the 
closure  of  the  port. 

This  theoretical  diagram  being  for  the  present  assumed  to  be 


280  THE   engineer's    pi  ANDY-BOOK. 


perfect,  not  in  the  sense  of  representing  the  best  conditions  in  an 
economical  point  of  view,  but  only  the  most  perfect  performance 
possible  under  given  conditions,  is  nevertheless  the  standard  with 
which  the  actual  one  is  to  be  compared,  and  by  which  it  is  to  be 
judged.  For  this  purpose  it  is  customary  to  draw  it  around  the 
actual,  so  that  the  imperfections  of  the  latter  may  be  readily  seen 
and  their  magnitude  estimated. 

Application  of  the  Theoretic  Curve. 

On  tracing  the  theoretic  curve  on  diagrams  from  different 
engines,  a  great  difference  in  the  degree  of  theoretical  correctness 
shown  in  their  expansion  curves  is  revealed.  The  deviation  from 
the  theoretical  is  always  in  the  direction  of  a  higher  terminal 
pressure,  unless  it  is  caused  by  excessive  piston  leakage.  This 
may  be  explained  on  two  suppositions,  viz.,  leakage  of  the  cut- 
off valves,  and  evaporation  of  the  spray  or  water  of  supersat- 
uration  in  the  steam  during  expansion  as  the  pressure  decreases. 
Till  recently  the  former  was  the  only  explanation  offered,  but,  in 
more  modern  times,  the  latter  has  almost  entirely  displaced  it. 
There  is  no  doubt  that  both  causes  are  in  some  degree  responsible 
for  the  phenomenon,  but  the  diagram  itself  seldom  furnishes  any 
reliable  indications  pointing  to  either  cause  to  the  exclusion  of  the 
other ;  nor  does  a  study  of  the  conditions  under  which  the  greatest 
incorrectness  shows  itself  throw  much  light  on  the  subject.  As  a 
general  rule,  large  engines  give  more  correct  expansion  curves  than 
small  ones,  though  numerous  exceptions  are  met  with  in  both 
cases. 

Incorrectness  is  generally  less  with  heavy  loads  than  with  light 
ones.  But  both  the  foregoing  facts  can  be  explained  on  either 
theory,  since,  with  equal  care  in  the  fitting  of  the  valves,  a  large 
engine  will  leak  less  in  proportion  to  the  amount  of  steam  used 
than  a  small  one.  But  the  evaporation  of  the  spray  will  be  less 
perfect  in  the  former  than  in  the  latter,  owing  to  the  longer  time 
occupied  in  effecting  a  given  degree  of  expansion,  during  which 


THE   ENGINEER'S  HANDY-BOOK. 


281 


the  heat  of  the  water,  instead  of  being  effective  for  evaporation, 
will  be  dissipated.  In  small,  fast-running  engines  the  steam  under- 
goes a  more  rapid  expansion,  and  the  heat,  rendered  sensible  hy 
the  removal  of  the  pressure,  has  less  time  to  be  taken  up  by  the 
cylinder  walls,  and  is  consequently  more  effective  in  vaporizing 
the  moisture.  Another  fault  in  small  engines  is  imperfection  in 
the  cut-off  valves.  Both  causey  afford  better  facilities  to  operate 
with  an  early  than  with  a  late  cut-off,  the  longer  time  afforded  by 
the*former,  and  the  less  pressure  under  the  valve,  being  favorable 
to  the  greatest  leakage  ;  and  the  greater  the  change  of  pressure  is, 
the  more  favorable  it  will  be  to  the  evaporation  of  the  moisture. 

If,  however,  the  deviation  should  (other  things  being  equal)  be 
found  to  be  greatest  when  the  water  is  high  in  the  boilers,  or  when 
the  steam  is  being  rapidly  generated,  that  fact  would  point  to  the 
spray  theory  as  the  undoubted  cause  of  part  of  it.  Such  appears 
to  be  the  case  to  some  extent,  though  the  observations  taken  on 
that  point  have  not  been  numerous  and  careful  enough  to  be  of 
much  value.  But,  whatever  may  be  the  cause  of  the  phenom- 
enon, it  is  so  general  that,  whenever  a  very  correct  curve  is  met 
with,  the  suspicion  of  piston  or  other  leakage,  the  tendency  of 
which  is  to  lower  the  pressure  during  expansion  is  always  justly 
raised,  and  should  be  disposed  of  by  test  or  otherwise,  before  such 
a  curve  can  be  confidently  accepted  as  evidence  of  correct  per- 
formance. Nevertheless,  very  correct  curves  are  sometimes  met 
with  when  piston  leakage  does  not  exist. 

The  most  obvious  lesson  to  be  deduced  from  the  facts  at  present 
in  our  possession,  seems  to  be  that,  when  any  considerable  in- 
correctness is  met  with  in  the  curves  of  the  diagrams  taken  from 
large  engines,  a  considerable  amount  of  leakage  may  be  confi- 
dently inferred.  But,  in  the  case  of  small  engines,  particularly 
fast-running  ones,  the  amount  of  incorrectness  which  may  be 
caused  by  re-evaporation  is  undoubtedly  greater  than  in  large 
ones ;  but  even  in  them  the  cut-off  valves  should  not  be  too  read- 
ily excused  without  examination. 
24  * 


282 


THE   ENGINEEH^S  HANDY-BOOK. 


The  Initial  Pressure,  or  Steam-Line. 

A  close  approximation  of  the  steam-line  of  an  automatic  cut- 
off diagram  to  the  boiler  pressure  is  rightly  regarded  as  an  indi- 
cation of  good  construction  and  performance.  Other  things  being 
equal,  that  engine  which  most  nearly  obtains  the  highest  boiler 
pressure  on  its  piston  at  the  commencement  of  the  stroke,  may 
cut  off  the  earliest  —  attain  the  highest  ratio  of  expansion  —  and 
exhaust  the  steam  at  the  lowest  pressure.  The  last  condition  is  the 
test  of  all  improvements  designed  to  promote  steam  economy,  as,  if 
they  do  not  produce  a  lower  terminal  pressure  for  the  same  work, 
they  do  not  fulfil  the  conditions  for  which  they  were  intended.  It 
is  not  sufficient  to  rely  on  the  steam-gauge  as  a  test  of  the  steam- 
line,  unless  it  has  been  recently  tested  and  found  correct.  Most 
steam-gauges  deteriorate  by  use,  especially  if  exposed  to  undue 
heat  or  cold.  When  practicable,  the  engine  should  be  stopped 
and  blocked,  or  placed  on  the  centre,  steam  admitted  to  the  indi- 
cator at  full  pressure,  and  a  line  traced  by  hand.  If  this  has  been 
done,  and  a  difference  of  four  or  five  pounds  between  boiler  and 
initial  pressure  be  detected,  how  is  the  difference  to  be  accounted 
for?  The  pipe  may  be  too  small,  long,  or  crooked,  or  the  ports 
be  inadequate ;  or  both  these  defects  may  exist.  To  test  this 
matter,  a  connection  should  be  made  between  the  indicator  and 
the  steam-pipe  above  or  below  the  throttle,  as  may  be  thought 
preferable.  By  means  of  this  connection,  a  diagram  representing 
the  fluctuations  of  pressure  in  the  pipe  is  produced  over  the  engine 
diagram.  A  diagram  produced  in  this  way  will  show  whether 
the  loss  of  pressure  is  due  to  the  ports  or  the  pipe.  In  such  a 
case,  the  pressure  falls,  when  it  is  admitted  to  the  cylinder,  until  it 
exceeds  the  initial  pressure  but  little  more  than  one  pound.  Then, 
as  soon  after  the  steam  is  cut  off,  as  the  space  immediately  above 
the  cut-off  valve  can  fill,  the  pressure  rises,  and  the  momentum 
of  the  steam  in  the  pipe  evidently  carries  it  above  that  of  the 
boiler,  and  about  the  middle  of  the  stroke  it  falls  again,  evidently 
going  below  the  boiler  pressure.    At  about  three-fourths  of  the 


THE   engineer's    HANDY-BOOK.  288 

stroke  it  rises  again,  but  this  time  not  so  high  as  it  did  at  its  first 
rise,  probably  not  above  boiler  pressure.  These  secondary  fluctu- 
ations possess  no  special  significance,  except  as  showing  that  the 
boiler  pressure  is  to  be  determined  by  finding  the  mean  of  their 
extremes.  Their  frequency  during  the  stroke  will  depend  on  the 
length  of  the  pipe  as  determining  their  frequency  in  time,  and  on 
the  speed  of  the  engine  as  determining  their  relative  frequency. 
The  pressure  of  the  steam  also  aflfects  them,  as  high-pressure  steam 
is  denser  than  low.  The  trouble  involved  in  making  the  necessary 
connection  for  such  a  diagram  will  of  course  exclude  them  in  most 
cases,  but  their  value  to  the  engineer,  as  a  means  of  arriving  at 
<jorrect  proportions  for  the  pipes  and  ports,  will  be  apparent. 

The  Mean  Effective  Pressure. 

Whatever  uncertainty  may  attach  to  the  inferences  deduced 
from  indicator  diagrams,  there  is  every  reason  to  believe  that, 
provided  that  the  spring  is  correct,  the  instrument  in  good  work- 
ing  order,  and  its  indications  mathematically  calculated,  the  con- 
clusions will  be  reliable.  The  usual  method  of  calculating  the 
mean  eflTective  pressure  is  to  divide  the  diagram  into  any  suitable 
number  of  equal  spaces  by  lines  or  ordinaies,  to  measure  the  centre 
of  each  space  with  the  proper  scale,  and  to  take  the  average  of  the 
several  pressures  by  dividing  their  sum  by  their  number.  But 
since  it  is  easier  to  measure  on  a  line  than  to  guess  at  the  centre 
between  two  lines,  it  will  be  preferable  to  make  the  first  and  last 
spaces  half  the  width  of  the  rest,  which  w^ill  make  the  lines  stand 
in  the  centres  of  equal  spaces.  The  measurements  are  then  taken 
on  them.  Diagram  No.  1,  page  291,  is  lined  in  this  manner. 
The  most  expeditious  and  accurate  method  of  obtaining  the 
average  of  these  ordinates  is  to  take  a  slip  of  paper,  apply  its 
edge  to  each  of  them  in  succession,  and  mark  their  combined 
length  on  it.  This  length  in  inches  multiplied  by  the  scale  of  the 
spring  used,  and  the  product  divided  by  the  number  of  ordinates 
measured,  will  give  the  desired  average.   By  using  a  sharp-pointed 


284         THE  engineer's  handy-book. 


instrument,  as  the  point  of  a  knife,  thrusting  it  into  the  pnper  at 
the  f  )ot  of  each  ordinate,  moving  it  to  the  top  of  the  next,  and 
carrying  the  strip  with  it,  the  measurement  may  be  taken  with 
great  ease  and  rapidity. 

The  simplest  method  is  to  measure  the  ordinates  between  the 
direct  and  counter-pressure  lines.  This  will  give  results  accurate 
enough  for  most  purposes ;  in  fact,  it  will  give  the  mean  average 
of  the  two  ends  with  entire  accuracy,  and  this  must  always  be  ob- 
tained as  a  basis  for  calculating  the  power  of  the  engine.  But, 
since  a  diagram,  from  either  end  of  the  cylinder,  represents,  by  its 
upper  line,  the  pressure  which  impels  the  piston  during  one  stroke, 
and  by  its  lower,  the  counter-pressure  which  opposes  it  during  the 
stroke  in  the  opposite  direction,  it  follows  that,  from  either  diagram 
alone,  a  corrrect  balance  for  either  of  the  two  strokes  which  it 
represents  cannot  be  struck.  To  do  this,  the  mean  counter-pressure 
of  the  one  must  be  deducted  from  the  mean  impelling  pressure  of  the 
other.  To  obtain  these  pressures  separately,  it  is  necessary  to  draw 
and  measure  the  ordinates  from  the  lines  representing  them  to  the 
vacuum  line.  This,. however,  is  unnecessary,  except  for  very  ac- 
curate analysis.  In  general,  the  counter-pressure  of  the  two  strokes 
will  be  very  nearly  equal,  especially  if  the  exhaust  and  cushion 
are  properly  equalized  ;  and  even  where  they  are  unequal,  the  final 
average  of  the  two  ends  will  be  correct. 

The  number  of  ordinates  may  preferably  be  one-fourth,  one- 
third,  one-half,  or  equal  to  the  number  representing  the  scale  used  ; 
in.  which  case  it  will  only  be  necessary  to  multiply  the  combined 
length  of  the  ordinates  (or  the  string,  as  it  may  be  called)  by  4, 
3,  or  2,  as  the  case  may  be,  to  obtain  the  desired  result.  If  the 
number  is  equal  to  the  scale,  the  multiplier,  being  1,  need  not  be 
used.  Thus,  suppose  the  scale  to  be  40,  the  number  of  ordinates 
20,  and  the  string  14^  inches.  As  the  scale  represents  twice  the 
number  of  ordinates,  the  string  being  multiplied  by  2  will  give  a 
product  of  29  lbs.  mean  pressure.  Or  suppose  diagrams  to  be 
taken  from  both  ends  of  the  cylinder,  either  on  the  same  paper  or 
separately,  and  the  one  to  be  calculated  and  averaged  with  the 


THE    engineer's  HANDY-BOOK. 


286 


other  The  string  of  both  may  be  taken  together  on  the  same 
strip,  and  if  the  scale  is  twice  the  number  of  ordinates,  the  length 
of  the  string  will  give  the  mean  pressure  at  once  without  multi- 
plying. When  taking  such  a  continuous  string  for  two  diagrams, 
the  termination  of  the  first  should  be  marked  with  a  pencil,  so 
that  the  two  may  be  compared. 

When  diagrams  are  met  with,  in  which  the  expansion  curve 
crosses  the  counter-pressure  line,  the  string  should  be  taken  from 
the  beginning  up  to  the  point  where  the  lines  cross,  and  after  that 
in  a  reverse  direction  on  the  strip,  so  as  to  cancel  the  part  of  the 
string  already  made.  When  the  terminal  end  is  reached,  what 
remains  of  the  string  first  made  will  give  the  mean  effective  press- 
ure (M  E.  P.)  in  the  usual  way ;  or  the  total  mean  impelling  and 
counter-pressure  above  vacuum  may  be  found  separately,  and  their 
diflference  ascertained. 

To  Space  the  Ordinates. 

Draw  vertical  lines  touching  the  ends  of  diagram  No.  1,  A  B 
E  ly  and  apply  a  rule  across  them  in  a  more  or  less  oblique  direc- 
tion, till  some  division  on  the  rule,  as  j^,  r2»  tV»  I>  ?j  ^^'iH  divide 
the  distance  between  the  points  where  the  rule  crosses  the  lines, 
the  desired  number  of  two  or  three  times  the  number  of  times. 
Thus  the  line  H  C  I,  in  diagram  No.  1,  is  3|  inches  long,  and 
contains  the  j'g  division  60  times ;  consequently,  ^%  pointed  off  at 
each  end,  and  for  the  other  spaces,  will  correctly  divide  the 
diagram  for  20  ordinates.  With  a  little  greater  obliquity  the  dis- 
tance would  be  4  inches,  when  ^  inches  would  be  right  for  the 
end  spaces,  and  -f^  for  the  rest. 

To  Calculate  the  Indicated  Horse-Power  (I.  H.  P.). 

Multiply  the  speed  of  the  piston  in  feet  per  minute  by  the  area 
of  the  piston  in  square  inches,  and  divide  the  product  by  33,000. 
The  result  will  be  the  H.  P.  for  each  pound  of  M.  E.  P.,  or  the 


286         THE  engineer's  handy-book. 

H.  p.  value  of  each  pound.  See  table  on  page  290,  Then  multiply 
the  M.  E.  P.  by  this  value.  This  method  is  preferable  to  multi- 
plying by  the  M.  E.  P.  before  dividing,  as,  when  several  diagrams 
from  the  same  engine  representing  varying  loads  are  to  be  calcu- 
lated, the  value  when  once  obtained  will  answer  for  all,  the  speed 
being  practically  the  same  in  each  case.  The  area  of  the  piston- 
rod  is  generally  ignored  in  such  calculations,  though  it  will  dimin- 
ish the  area  of  one  side  of  the  piston  about  ^^q. 

Theoretical  Economy. 

If  the  steam  used  by  an  engine  was  known  to  be  saturated,  and 
at  the  same  time  free  from  any  excess  of  water,  and  if  it  both 
entered  and  left  the  engine  in  that  condition,  it  would  be  easy  to 
calculate  from  the  diagram  the  amount  of  water  which  the  engine 
would  use  in  a  given  time,  supposing  it  to  be  practically  free  from 
leakage.  Under  such  conditions  the  expansion  and  compression 
curves  would  conform  rigidly  to  exact  theory,  and  the  total  piston 
displacement  for  one  stroke,  divided  by  the  volume  of  terminal 
pressure,  and  the  displacement  up  to  any  point  in  the  curve  di- 
vided by  the  volume  of  the  pressure  at  that  point,  would  give  the 
same  result  wherever  the  point  was  taken,  which  result  would  be 
the  number  of  cubic  inches  of  water  used  during  that  stroke. 
Unfortunately,  the  nature  of  steam  is  such  that  no  exact  calcula- 
tions of  water  consumption  can  be  made.  Even  if  its  exact  con- 
dition as  it  enters  the  engine  is  known,  as  it  may  be  by  the  calor- 
imeter test,  its  capacity  for  receiving  and  parting  with  heat  is  so 
great  that  its  condition  changes  immediately  upon  entering  the 
cylinder,  so  that,  after  deducting  the  water  of  supersatu ration, 
known  to  be  present  before  it  enters  the  cylinder,  the  diagram 
will  still  fail  to  account  for  all  of  the  remainder.  Nevertheless 
such  calculations  are  frequently  made,  and  as  a  means  of  ascer- 
taining the  relative  economy  of  different  engines,  and  of  different 
loads,  pressures,  and  adjustments  in  the  same  engine,  they  possess 
great  value,  since,  whatever  uncertainty  may  exist  as  to  the  unin* 


THE   ENGINEER'S   HANDY-BOOK.  287 

dicated  consumption,  it  may,  so  far  as  the  engine  is  concerned, 
be  assumed  to  be  the  same  in  each  of  the  cases  under  compar- 
ison. 

When  it  is  desired  to  approximate  as  nearly  as  possible  to  the 
actual  consumption  by  calculation,  a  certain  amount  must  be 
added  to  the  theoretical  result.  This  amount  varies  from  10  to  50 
per  cent.,  according  as  the  conditions  are  more  or  less  favorable ; 
but  when  they  are  so  unfavorable  as  to  require  an  addition  of  50 
per  cent.,  they  are  obviously  so  bad  as  to  call  for  repairs  and 
changes,  rather  than  elaborate  calculations.  When  the  conditions 
are  generally  good,  a  careful  examination  of  them  will  make  it 
possible  to  fix  the  margin  of  uncertainty  within  tolerably  narrow 
limits.  A  large  engine,  with  well-jacketed  cylinder  and  tight-fitting 
valves  and  piston,  will  generally  require  at  least  10  per  cent,  ad- 
dition, independent  of  the  percentage  of  unevaporated  spray, 
which  may  exist  in  the  steam  with  which  it  is  supplied,  and  this, 
unless  the  boiler  is  so  set  as  to  superheat  the  steam,  will  require 
from  10  to  25  per  cent.  more.  In  fact,  the  margin  of  uncertainty 
due  to  the  boiler  is  much  greater  than  that  due  to  the  engine,  as 
not  only  will  differently  constructed  boilers  vary  greatly  in  the 
amount  of  unevaporated  water  given  off*,  but  great  difference  will 
be  found  to  exist  with  the  same  boiler,  according  to  the  height  the 
water  is  carried,  the  rapidity  with  which  it  is  evaporated,  the 
amount  of  impurities  present  in  the  feed-water,  or  which  have 
accumulated  in  the  boiler,  and  many  other  conditions.  Thus  a 
rapidly  fired  generator,  containing  a  large  area  of  heating  surface 
in  proportion  to  the  amount  of  water  and  little  steam  room  and 
superheating  surface,  may,  and  often  will,  give  off*  nearly  or  quite 
as  much  unevaporated  water  as  is  contained  in  the  steam.  The 
only  fair  way  to  test  the  performance  of  an  engine  is  to  test  the 
steam  as  it  enters  it,  both  as  to  moisture  and  heat.  It  should 
also  be  borne  in  mind  that,  according  to  Trowbridge's  tables,  the 
difference  between  the  economy  of  engines  of  over  ten  cubic  feet 
capacity  of,  cylinder  and  those  under  one  cubic  foot,  is  about  12 
j-er  cent,  in  favor  of  the  larger  size. 


288  ► 


THE   engineer's  HANDY-BOOK. 


How  to  Calculate  Theoretical  Rate  of  Water  Consump- 
tion. 

The  total  displacement  per  stroke  in  cubic  inches  divided  by 
the  volume  of  the  steam  at  release  pressure,  and  the  quotient 
multiplied  by  the  number  of  strokes  per  hour,  will  give  the  total 
cubic  inches  used  per  hour.  This,  divided  by  27*648,  the  number 
of  cubic  inches  of  water  per  pound,  will  give  the  total  number 
of  pounds  used  per  hour,  which,  if  divided  by  the  I.  H.  P.,  will 
give  the  result  in  pounds  per  I.  H.  P.  per  hour.  This  is  the  usual 
method ;  but,  when  the  rate  only  is  desired,  a  shorter  process  may 
be  adopted,  based  on  the  fact  that,  from  a  given  diagram,  the  re- 
sult would  be  the  same,  whether  the  calculations  are  based  on  the 
actual  size  of  the  engine,  or  some  other  size  is  assumed,  say  a 
smaller  size;  as,  although  the  total  consumption  would  be  changed, 
the  divisor  would  also  be  proportionately  changed. 

Suppose  the  engine  to  be  of  such  displacement  as  to  develop 
one  horse-power  with  one  pound  pressure,  and  that  it  is  driven  by 
that  pressure  of  water  instead  of  steam.  It  being  but  one  horse- 
power, its  total  consumption  per  hour  and  per  horse-power  per 
hour  will  be  the  same.  Being  driven  by  water,  its  displacement 
will  be  its  water  consumption,  which  will  be  obtained  as  follows: 
A  horse-power  is  33,000  lbs.  lifted  one  foot  high  per  minute,  or 
33,000  X  60=--4 ,980,000  lbs.  per  hour,  or  1,980,000  x  12=22,760,000 
lbs.  lifted  one  inch  per  hour,  which  would  be  the  displacement  of 
such  an  engine  in  cubic  inches,  and  consequently  its  consumption 
in  cubic  inches  of  water  when  driven  by  water.  Then,  taking 
27*648  cubic  inches  of  water  per  lb.,  we  have  22,760,000  27*648 
=  859,375  as  its  rate  of  consumption  in  lbs.  of  water  per  H.  P. 
per  hour.  Then,  if  the  pressure  were  greater  than  one  lb.,  the 
amount  used  would  be  as  many  times  less  than  the  above,  as  the 
pressure  was  greater  than  one  lb. ;  and  also,  if  it  were  driven  by 
steam  instead  of  by  water,  the  amount  used  would  be  as  much 
less,  as  the  volume  of  steam  at  the  terminal  pressure  was  greater 
than  an  equal  weight  of  water.     It  follows  that  if  we  divide 


THE   engineer's  HANDY-BOOK, 


289 


859,375  by  the  product  of  the  mean  effective  pressure,  and  the 
volume  of  the  total  terminal  pressure  of  the  diagram  under  analy- 
sis, the  quotient  will  be  the  desired  rate,  whatever  the  size  and 
speed  of  the  engine.  The  use  of  this  constant  number  renders 
the  operation  more  easy  and  short,  and,  except  in  the  case  of  the 
compound  engine,  entirely  independent  of  all  data  except  those  fur- 
nished by  the  diagram  itself,  the  scale  of  indicator  being  known. 

The  terminal  pressure  for  this  and  subsequent  rules  is  found, 
when  the  exhaust  takes  place  before  the  end  of  the  stroke  is 
reached,  by  continuing  the  expansion  curve  to  the  end  of  the 
stroke.  In  other  words,  it  is  not  what  the  pressure  may  be  at  the 
moment  of  release,  but  what  it  would  have  been  if  it  had  not 
been  released  until  the  end  of  the  stroke. 

How  to  apply  the  rule  to  diagrams  taken  from  compound  en- 
gines when  the  strokes  of  the  two  cylinders  are  equal.  Multiply 
the  M.  E.  P.  of  the  low-pressure  cylinder  diagram  by  the  area  of 
its  piston,  and  divide  the  product  by  the  area  of  the  piston  of  the 
high-pressure  cylinder.  The  quotient  will  be  the  pressure,  which, 
acting  on  the  low-pressure  piston,  will  be  equivalent  in  energy  to 
that  acting  on  the  high-pressure  piston.  Then  add  this  quotient 
to  the  M.  E.  P.  of  the  high-pressure  cylinder,  and  with  its  mean 
pressure  so  augmented  treat  it  in  all  respects  as  an  ordinary  dia- 
gram. Or  the  process  may  be  reversed,  i.  e.,  the  diagram  from 
the  low-pressure  cylinder,  with  its  M.  E.  P.  augmented  by  the 
quotient  of  the  product  of  the  area  and  M.  E.  P.  of  the  horse- 
power cylinder  divided  by  the  area  of  the  low-pressure  cylinder, 
may  be  treated  as  an  ordinary  diagram ;  but  the  result  by  this 
method  will  be  less  than  by  the  first. 

When  the  two  cylinders  have  different  strokes  as  well  as  dif- 
ferent piston  areas,  multiply  together  the  M.  E.  P.  piston  area, 
and  stroke  of  the  high-pressure  cylinder,  and  divide  the  product 
by  the  product  of  the  piston  area  of  the  low-pressure  cylinder 
multiplied  by  its  stroke.  The  quotient  will  be  the  amount  to  aug- 
ment the  M.  E.  P.  of  the  horse-power  cylinder  before  treating  it 
as  a  simple  diagram. 

25  T 


290 


THE   engineer's  HANDY-BOOK. 


The  same  calculations  may  be  more  conveniently  made  by 
means  of  the  following  table ;  to  use  it,  proceed  according  to  the 
following  rule : 

Find  under  P  the  number  which  corresponds  nearest  to  the 
terminal  pressure  of  the  diagram,  and  multiply  the  terminal 
pressure  by  the  number  opposite  it  to  the  right  under  W,  and  di- 
vide the  product  by  the  M.  E.  P. ;  the  quotient  will  be  the  rate  of 
water  consumption  in  lbs.  per  1  horse-power  per  hour. 


p. 

w. 

P. 

w. 

P. 

w. 

P. 

w. 

P. 

w. 

5 

37-95 

27 

34-37 

49 

33-18 

71 

32-46 

93 

31-96 

6 

37-54 

28 

34-29 . 

50 

33-14 

72 

32-43 

94 

31-94 

.7 

37-22 

29 

34-22 

51 

33-10 

73 

32-40 

95 

31-92 

8 

36-93 

30 

34-15 

52 

33-06 

74 

32-38 

96 

31-90 

9 

36-67 

31 

34-08 

53 

33-02 

75 

32-36 

97 

31-88 

10 

36-44 

32 

34-01 

54 

32-98 

76 

32-34 

98 

31-86 

36-24 

33 

33*95 

55 

32-94 

77 

32-32 

99 

31-84 

12 

36-06 

34 

33-89 

56 

32-91 

78 

32-30 

100 

31-82 

13 

35-89 

35 

33-83 

57 

32-88 

79 

32-28 

101 

31-80 

14 

35-73 

36 

33-77 

58 

32-85 

80 

32-26 

102 

31-78 

15 

35-59 

37 

33-72 

59 

32-82 

81 

32-23 

103 

31-77 

16 

35-46 

38 

33-67 

60 

32-79 

82 

32-20 

104 

31-75 

17 

35-34 

39 

33-62 

61 

32-76 

83 

32-18 

105 

31-73 

18 

35-22 

40 

33-57 

62 

32-73 

84 

32-16 

106 

31-71 

19 

35-10 

41 

33-52 

63 

32-70 

85 

32-14 

107 

31-69 

20 

34-99 

42 

33-47 

64 

32-67 

86 

32-12 

108 

31-67 

21 

34-89 

43 

33-42 

65 

32-64 

87 

32-09 

109 

31-65 

22 

34-79 

44 

33-38 

66 

32-61 

88 

32-07 

110 

31-63 

23 

34-70 

45 

33-34 

67 

32-58 

89 

32-05 

111 

31-61 

24 

34-61 

46 

33-30 

68 

32-55 

90 

32-03 

112 

31-59 

25 

34-53 

47 

33-26 

69 

32-52 

91 

32-00 

113 

31-57 

26 

34-45 

48 

33-22 

70 

32-49 

92 

31-98 

114 

31-55 

Example  from  same  diagram.  The  terminal  pressure  is  25-5  lbs., 
and  the  mean  of  the  numbers  under  W,  opposite  to  25  and  26 
(34-50  and  34-41),  is  34-45.  The  mean  effective  pressure  being 
30-5,  the  operation  is  as  follows  :  25-5  X  34-45  30*5  =  28-8  lbs. 
per  horse-power  per  hour. 

As  a  matter  of  course,  the  theoretical  rule  of  water  consump- 
tion, as  deduced  from  indicator  diagrams,  can  never  be  fully 
realized  in  practice.    It  can  only  be  approximated. 


THE  engineer's  HANDY-BOOK. 


291 


Indicator  Dia^ams. 

All  indicator  diagrams  are  the  perfect  pictures  of  the  perform- 
ances of  the  engines  from  which  they  are  taken,  provided  the  in- 
dicator is  in  good  order.  There  are  two  senses  in  which  a  diagram 
is  said  to  be  perfect  or  imperfect.  First,  it  may  be  in  perfect  con- 
formity to  existing  conditions,  as  clearance,  load,  steam-pressure, 
etc.,  though  all  of  these  conditions  may  be  far  from  the  best ;  or, 
second,  it  may  not  only  conform  to  the  above  conditions,  but  it 
may  represent  the  best  attainable  conditions,  which  would  include 
no  clearance  at  all,  which  is  unattainable. 


Explanatory  Diagram  No.  1. 


In  diagram  No.  I,  B  C  shows  the  steam  line;  C,  point  of  cut-off; 
CD,  expansion  curve ;  D,  exhaust ;  D  E,  exhaust  line ;  EF,  counter- 
pressure  line ;  jP,  point  of  exhaust-closure ;  F  G,  compression  curve ; 
G  By  admission  line ;  A  A,  atmospheric  line ;  V  V,  vacuum  line ; 
HHy  line  representing  the  clearance ;  0  0  0,  ordinates  for  ascertain- 
ing the  average  pressure ;  /,  continuation  of  the  expansion  curve  to 
end  of  stroke,  to  give  the  terminal-pressure  for  the  purpose  of  calcu- 
lating theoretical  consumption ;  J,  the  point  in  the  compression  curve 
where  the  pressure  equals  the  terminal ;  consequently,  IJ  is  the  pro- 
portion of  the  whole  stroke  taken  as  the  measure  of  the  consumption. 


292  THE   ENGINEER'S  HANDY-BOOK. 


Diagram  No.  2  was  taken  from  a  Buckeye  automatic  cut-ofF 
engine  22  x  44;  piston  speed,  520  feet  per  minute;  scale,  40; 


Diagram  No.  2. 


clearance,  1*75  per  cent.;  mean  effective  pressure, 36  lbs.  It  shows 
very  perfect  performance  both  of  the  engine  and  indicator. 

Diagram  No.  3  was  taken  from  a  locomotive  built  at  the  Baldwin 


Diagram  No.  3. 


Locomotive  Works,  for  the  Pennsylvania  Railroad  Company,  to 
run  on  the  Philadelphia  and  Erie  Railroad.  Diameter  of  cylinder, 


THE   engineer's  HANDY-BOOK. 


293 


18  inches;  stroke,  22  inches;  speed,  93  revolutions  per  minute; 
boiler-pressure,  115  lbs.  per  square  inch;  initial-pressure,  100  lbs.; 
mean  effective  pressure,  86*60  lbs.;  clearance,  4  per  cent.  At  the 
time  the  diagram  was  taken,  the  engine  was  pushing  a  train  of  15 
loaded  cars,  whose  gross  weight  was  302  tons,  throttle-valve  wide 
open,  against  a  grade  of  74  feet  rise  per  mile.  Adhesion  per  ton 
of  load  600,  resistance  per  ton  due  to  grade  35*7  lbs.  The  slight 
rounding  of  the  induction  corner  was  probably  caused  by  too 
much  pressure  on  the  pencil,  which  prevented  it  from  rising  till 
after  the  paper  started  to  move.  The  diagram  is  very  good.  The 
expansion  curve,  as  far  as  can  be  observed  from  its  limited  extent, 
is  correct,  and  its  compression  curve  very  nearly  so. 

Diagram  No.  4  was  taken  from  a  Wardwell  valveless  engine 
on  exhibition  at  the  Centennial  Exposition  held  at  Philadel- 


Diagram  No.  4. 


phia.  The  conditions  under  which  the  diagram  was  taken  are 
not  specified,  but  it  will  be  observed  that  the  exhaust-port  opens 
quite  late  and  quick,  which  explains  the  fact  that  the  curve  is  all 
on  the  lowev  corner.  The  cut-off  is  quick  and  sharp.  The  induc- 
tion and  compression  lines  are  also  good.  The  lateness  of  the  ex- 
haust is  a  necessary  result  of  the  movement  which  produces  it,  as 
it  is  effected  by  a  partial  rotation  of  the  piston-head,  derived  from 
25^ 


294 


THE   ENGINEER'S  HANDY-BOOK. 


the  lateral  vibration  of  the  connecting-rod,  which  gives  a  movement 
exactly  equivalent  to  that  of  an  eccentric  without  angular  advance. 
Diagrams  No.  5  were  taken  from  an  old  Corliss  engine  that 

had  been  running  in 
the  penitentiary  at 
Jackson,  Michigan, 
for  about  25  years. 
Scale,  40;  clearance 
about  3  per  cent.; 
mean  effective  press- 
ure, 47*5  lbs. ;  mean 
of  the  two  ends,  47| 
lbs.  It  possesses  no 
special  interest,  save 
to  show  the  effects  of 
adjustment  due  to 
long  wear  and  use, 
without  the  applica- 
tion of  an  indicator  or 
any  other  test.  The 
excessively  late  in- 
duction would  cause 
a  perceptible  loss  of 
useful  effect  in  the 
steam.  The  exhaust 
is  much  less  perfect 
from  one  end  than 
from  the  other,  and 
much  of  the  benefit 
of  the  vacuum  is 
thereby  lost.  The 
pencil  was  held  on 
Diagrrams  No.  5.  during  several  revo- 

lutions, and,  the  governor  being  over-sensitive  and  fluctuating, 
different  lines  were  drawn  at  each  revolution. 


THE   engineer's  HANDY-BOOK. 


295 


Diagram  No.  6  was  taken  from  a  Harris  Corliss  engine  oper- 
ating at  the  Cincinnati  Industrial  Exposition  of  1875.  Size,  16 
X  48;  speed,  60  revolu- 
tions, or  480  feet  of  piston 
speed  per  minute.  Both 
the  isothermal,  J,  and  the 
adiabetic  curves  are  drawn. 
In  tracing  the  latter,  the 
following  process  was  used. 
The  horizontal  lines,  A,  B, 
C,  D,  E,  F,  G,  represent  to- 
tal pressures  (above  vacu- 
um) of,  respectively,  90, 80, 
70,  60,  50,  40,  and  30  lbs., 
the  volumes  of  which  are 
298,  333,  378,  437,  518, 
640,  and  838.  At  the  point, 
H,  where  the  curve  termi- 
nates, the  total  pressure  is 
19  lbs.,  the  volume  of  which 
is  1290.  Now,  it  is  evident 
that  if  the  distance,  H  «/, 
which  is  4*7  inches,  repre- 
sents 1290,  the  distance, 
G  Jy  representing  838, 
(the  volume  of  30  lbs.,) 
will  be  proportionately  as 
much  shorter  than  H  J 
as  838  is  less  than  1290. 
Hence,  the  formula,  1290  : 
4-7  :  :  838  :  3  05,  or 
4-7  X  838  . 
~2290  '  ^^^^ 

this  distance  (3*05)  from 

the  clearance  line,  J,  to  Diagram  No.  6, 


296 


THE   ENGINEER'S  HANDY-BOOK. 


that  point  in  the  curve  which  shows  a  pressure  of  30  lbs.   In  like 


manner  the  formula  for  the  point,  F,  will  be 
4-7  X  518 


4-7  X  640 
1290 


for  E, 


1290 


-,  and*so  on  for  the  other  lines,  2>,  C,B,A.    The  fore- 


going process  may,  however,  be  shortened. 


Diagram  No.  7. 


Diagram  No.  7 

was  taken  from  a 
Holly  engine  lo- 
cated at  the  water- 
works of  Rochester, 
N.  Y.  Size,  16  X 
26*9  inches ;  speed 
not  given,  but  it  va- 
ries greatly,  as  it  is 
regulated  by  the  wa- 
ter-pressure ;  mean 
effective  pressure, 
30 lbs.;  scale,  32 lbs. 
The  cut-off  valves 
of  these  engines  con- 
sist of  a  single-pop- 
pet valve  placed  on 
the  cover  of  the 
steam -chest,  which 
cuts  off  the  steam 
for  both  strokes ; 
hence,  all  the  steam 
in  the  chest  is  sub- 
ject to  expansion 
along  with  that  in 
the  cylinder,  which 
has  the  effect  of  enor- 
mous clearance  on 
the  diagram.  The 
theoretical  curve 


THE   engineer's  HANDY-BOOK. 


297 


shown  is  not  based  on  the  actual  clearance  subject  to  expansion, 
but  on  a  reasonably  small  amount,  not  greater  than  the  average 
of  true  automatics 
of  good  construction  ; 
consequently,  it  is  not 
a  test  of  the  conform- 
ity of  the  curve  to  the 
actual  conditions,  but 
rather  a  means  of 
comparing  the  eco- 
nomical results  of 
such  an  arrangement 
with  engines  of  the 
best  automatic  type. 

Diagram  No.  8  was 
taken  from  a  Wheel- 
ock  automatic  cut-off 
engine  on  exhibition 
at  the  Centennial  Ex- 
position. Size,  18  X 
48 ;  clearance,  4J  per 
cent. ;  scale,  30 ;  mean 
effective  pressure,  12; 
piston  speed,  50  revo- 
lutions, or  400  feet  per 
minute.  A  is  the  adi- 
abatic  and  I  the  isoth- 
ermal curve,  both  be- 
ing based  on  actual 
terminal  -  pressure- 
The  diagram  is  quite 
good  for  a  light  load, 
though  the  very  slight 
compression  is  not  in  Diagrram  No.  8. 

accordance  with  the  weight  of  opinion  as  to  what  constitutes  sound 
practice. 


298         THE  engineer's  handy-book. 


Diagrams  No.  9  were  taken  from  a  Cummer  slide-valve  engine, 

with  riding  cut-off,  built  at  De- 
troit, Michigan.  Size,  26  X  36 
inches ;  speed,  80  revolutions,  or 
480  feet  per  minute;  scale,  30; 
mean  effective  pressure  not  giv- 
en ;  clearance  is  unknown,  but  as- 
suming it  to  be  4  per  cent.,  which 
is  about  what  its  construction  re- 
quires, the  theoretical  curve  at 
one  end  shows  correct  perform- 
ance, but  that  at  the  other  shows 
considerable  deviation.  In  such 
a  case,  taking  the  size  of  the  en- 
gine into  consideration,  the  ex- 
planation of  this  defect  lies  be- 
tween two  suppositions,  1st,  that 
the  cut-off  valve  leaked  at  one 
end  and  not  at  the  other;  or,  2d, 
that  the  volume  of  clearance^  is 
greater  at  one  end  than  at  the 
other.  If  the  engine  had  been 
a  small  one,  the  supposition  of 
the  escape  of  the  expanding  steam 
from  the  right-hand  end  through 
a  leaky  slide-valve  would  be  ad- 
missible ;  but  the  curve  at  that 
end  is  just  what  an  engine  of  the 
size  given  should  produce  with- 
out leakage  of  any  kind;  hence, 
the  left  hand  is  the  one  to  which 
attention  is  directed  for  the  cause 
of  the  difference  between  the  two, 
and  the  supposition  of  a  leaky 
cut-off  valve  is  the  more  prob- 
Diagrama  No.  9.  able  one. 


THE  engineer's  HANDY-BOOK. 


2yy 


Diaqram  No.  10  was  taken  from  one  of  a  pair  of  16  X  30  inch 
single  slide-valve  engines,  which  were  attached  to  the  same  shaft 
witl  cranks  at  right  angles  to  each  other.  Thejnston  speed  wa. 
350  feet  per  minute;  mean  effective  pressure,  32-3  The  sudden 
termination  of  the  compression  curve  with  a  descendmg  hook  sug- 


Diagram  No.  10. 

gests  leakage  of  the  piston  or  valve.   The  more  rapid  fall  of  the 
expansion  curve  than  theory  requires,  strengthens  this  supposition 
and  points  to  the  piston  as  the  source  of  the  trouble.  _  The  rise  of 
counter-pressure  in  the  middle  of  the  return  stroke  is  due  to  the 
reaction  of  the  exhaust  of  the  other  engine. 


Diasrram  No.  11. 

Diagram  No.  II  was  taken  from  an  engine,  18  x  36,  in  a  mill 


300  THE  ENGINEER'S  HANDY-BOOK. 

in  Detroit,  Michigan.  The  cut-off  was  effected  by  a  special  cut 
off  valve  above  the  steam-chest,  operated  by  a  Kendall's  patent 
governor,  which  varies  the  throw  and  advance  of  an  eccentric 
on  the  shaft  by  an  arrangement  similar  to  that  of  the  link-motion 
of  a  locomotive.  The  most  striking  defect  is  the  extremely  late 
induction,  showing  a  displacement  of  the  eccentric,  leading  to  a 
loss  of  about  one-sixth  of  the  stroke.  The  exhaust  is  too  late, 
evidently  from  the  same  cause. 

Diagrams  No.  12  were 
taken  from  a  Brown  auto- 
matic cut-off  engine  on  ex- 
hibition at  the  Centennial 
Exposition.  Diameter  of 
cylinder,  15  inches;  stroke, 
38;  revolutions,  65;  scale, 
30  lbs.  They  show  wonder- 
ful conformity  to  theoreti- 
cal requirements,  and  that 
the  engine  and  indicator 
must  be  in  the  most  perfect 
order  to  produce  such  cards. 
The  unusually  sharp  cut- 
off corners  are  due  to  a  cer- 
tain extent  to  the  fact  that 
the  induction  and  cut-off 
valves  are  of  the  gridiron 
type,  and  that  the  indicator 
is  of  an  improved  pattern, 
with  exceptionally  light 
moving  parts ;  but  neverthe- 
less there  is  an  air  of  sus- 
picion about  them,  that  will 
leave  doubts  of  their  gen- 
Diagra^ms  No.  12.  uineness  in  the  minds  of  in- 

telligent engineers  ,who  understand  the  action  of  the  valves  of 
steam-engines.  { 


THE   ENGINEER'S  HANDY-BOOK. 


301 


Diagram  No.  13  was  taken  from  a  John  Cooper  engine,  built 
under  the  Babcock  and  Wilcox  patent,  at  Mount  Vernon,  Ohio. 
Diameter  of  cylinder,  20  inches ;  stroke,  36  inches ;  boiler-press- 
ure, 55  lbs.  per  square 
inch ;  speed,  60  revolu- 
tions per  minute ;  scale, 
30  lbs.  per  square  inch. 
It  shows  no  imperfec- 
tions worthy  of  note,  ex- 
cept the  imperfect  re- 
tention of  the  compres- 
sion-pressure, owing  un- 
doubtedly to  leakage 
either  of  the  piston  or 
slide  valve.  Such  a  de^ 
feet  is  a  very  common 
one,  and  may  appear 
when   no    other  evi- 
dences of  leakage  exist, 
in  which  case  it  is  prob- 
able that,  if  the  com- 
pression escapes  by  the 
piston,  the  leakage  ex- 
ists at  the  end  of  the 
stroke,  or,  if  it  escapes 
by  the  valve,  only  the 
portion  which  retains 
the  compression-press- 
ure fits  imperfectly.  In 
the  present  case  the 
compression  curve  com- 
mences promptly,  but 
succumbs  completely,  and  falls  again  before  admission,  show- 
ing that  the  leakage  commences  suddenly  near  the  end  of  the 
stroke. 

26 


Diagram  No.  13. 


302  THE   ENGINEER'S  HANDY-BOOK. 


Diagram  No.  14  was  taken  from  a  9  x  15  high-pressure  single 
slide-valve  engine.   Speed,  190  revolutions  per  minute;  scale,  40; 


Diagram  No.  14. 


clearance,  6'4  per  cent.;  mean  effective  pressure,  41  lbs.  It  will  be 
noticed  that  its  events  occur  late,  which  defects  arise  from  counter- 
pressure,  indicating  obstructed  exhaust  and  imperfect  rise  in  the 
compression-pressure,  suggesting  leakage  of  either  the  valve  or 
piston  by  which  the  compression-pressure  has  escaped. 


Diagrram  No.  15. 

Diagram  No.  15  was  taken  from  the  same  engine.  Its  defective 
performance,  as  shown  by  its  late  cut-off,  late  and  insufficient  ex- 


THE   engineer's  HANDY-BOOK. 


303 


haust,  and  its  excessive  counter-pressure,  all  tending  to  extrava- 
gant fuel  consumption,  speak  louder  than  words  of  the  vital  import- 
ance of  an  intelligent  use  of  the  indicator  by  engine  builders,  par- 
ticularly when  perfect- 
ing new  designs  and 
constructions.  The 
counter-pressure  was 
partly  due  to  a  con- 
tracted exhaust-nozzle 
used  to  create  draught ; 
but,  even  if  it  had  had 
ample  exhaust  capac- 
ity at  all  points  ex- 
cept at  the  nozzle,  the 
counter-pressure  cre- 
ated by  that  ought  not 
to  have  exceeded  one 
or  one  and  a  half  to 
two  pounds  per  square 
inch. 

Diagram  No.  16  is 

an  exact  transfer  from 
two  diagrams  taken 
separately  from  the 
same  end  of  the  cylin- 
der of  an  automatic 
cut-off  engine.  The 
dotted  lines  represent 
the  card  made  by  the 
Richards,  while  the 
plain  lines  represent 


Diagrram  No.  16. 


that  made  by  the  Thompson,  indicator.  A  comparison  reveals 
the  fact  that  the  correct  average  pressure  cannot  be  ascertained 
from  a  diagram  which  is  distorted  by  vibration,  and  also  that  it^! 
indications  are  deceptive  as  to  admission,  cut-off,  and  compression. 


304 


THE   ENGINEER'S  HANDY-BOOK. 


Diagrams  Nos.  17  and  18  were  taken  respectively  from  the  high- 
and  low-pressure  cylinders  of  the  compound  engines  of  the  steam- 
ship Pennsylvania,  of 
the  American  Line, 
built  by  Cramp  & 
Sons,  marine  engi- 
neers and  naval  archi- 
tects of  Philadelphia; 
speed,  58*3  revolutions 
per  minute.  The  dia- 
grams present  no  de- 
fects; the  slight  dif- 
ference in  the  mean- 
pressure  of  the  two 
ends  of  each  card  (as 
in  the  case  of  all  ver- 
tical engines)  is  due 
to  the  unbalanced 
weights  of  the  recip- 
rocating parts. 

The  theoretical 
clearance  is  about  10 
per  cent. ;  and,  as  this 
is  probably  not  far 
from  the  actual,  the 
expansion  curves  show 
very  correct  perform- 
ance. The  amount  of 
vacuum  shown  is  10  to 
lOi  lbs.,  which  isabove 
the  average  of  marine 
engines. 

As  these  engines  are  said  to  be  more  economical  than  any 
heretofore  used  on  ocean  steamers,  a  calculation  of  their  theoret- 
ical economy  will  not  be  without  interest.    Taking  the  steam  used 


Diagram  No, 


THE   engineer's    JI  A  N  J)  Y  -  BOO  K  . 


305 


by  the  small  cylinder  as  the  measure  of  consumption,  the  first 
process  is  to  find  for  it  the  equiv- 
alent of  the  mean-pressure  acting 
on  the  large  piston.  The  area 
of  the  small  cylinder  is  2574*1975 
square  inches,  and  that  of  the 
large  one  is  6379*4238  square 
inches.  The  M.  E.  P.  of  the 
small  cylinder  is  33'25  lbs.,  and 
that  of  the  other  9*25  lbs.  The 
rule  is  to  multiply  the  area  of 
the  large  piston  by  the  mean- 
pressure  acting  on  it,  and  divide 
the  product  by  the  area  of  the 
small  piston.  But,  in  the  pres- 
ent case,  it  will  involve  less  labor 
to  perform  the  division  first, 
that  is,  to  divide  the  area  of  the 
large  piston  by  that  of  the  small 
one,  and  multiply  the  quotient 
by  the  M.  E.  P.  of  the  large  one. 
Thus,  6379-4238  2574-1975  x 
9-25  =  19-33  lbs.,  which,  added 
to  the  M.  E.  P.  of  the  small  cyl- 
inder (33-25  -f  19-33  =  52*58 
lbs.),  gives  for  it  the  equivalent 
of  both,  52*58.  Then  the  vol- 
ume  of  the  average  terminal  (28 
lbs.)  being  895,  the  calculation 

•11  k       ^  n  859*375 

will  be  as  follows :   r^r^ 

895  X  52-58 

=  16.2  lbs.  From  this  the  de- 
duction for  compression  will  be 
about  3  per  cent.,  or  -48  lbs.,  leaving  (16*2  — -48)  15*70  lbs.  per 
I.  H.  P.  per  hour,  which  justifies  theoretically  the  claim  made 
26*  U 


Diagrram  No.  18. 


306 


THE   ENGINEER'S  HANDY-BOOK. 


for  these  engines.  The  engines  of  the  four  steamships  of  this  line 
gave  very  similar  diagrams. 

Diagrams  Nos. 
19  and  20  were 
taken  respective- 
ly from  the  high- 
and  low-pressure 
cylinders  of  the 
compound  en- 
gines of  the 
steamship  St. 
Paul,  built  by 
Cramp  &  Sons, 
of  Philadelphia, 
on  her  trial  trip, 
and  now  plying 
between  San 
Francisco,  Cal., 
and  Alaska. 
Scale  of  high- 
pressure  cylinder 
30  lbs.,  of  low- 
pressure  cylinder 
12  lbs.,  per  square 
inch.  The  data 
are  as  follows : 
steam,  67  lbs.  ; 
revolutions  per 
min.,  74 ;  cut-off, 
•25 ;  vacuum,  26 ; 
indicated  horse- 


Diagram  No.  19. 


power  of  high-pressure  cylinder,  262*5  ;  of  low-pressure  cylinder, 
'265*63 ;  total,  528*13.  Mean  effective  pressure  of  high-pressure 
cylinder,  43*125  ;  of  low-pressure  cylinder,  14*25  lbs.  The  termi- 
nal-pressures, as  shown  by  the  diagrams,  are  as  follows :  The  mean 


THE   IINGINEER's  HANDY-BOOK. 


307 


terminal-pressure  of  both  ends  of  the  high-pressure  cylinder  is  47 
lbs.  (above  vacuum);  volume,  550.  Of  the  low-pressure  cylinder  is 
11*25  lbs.  above  vac- 
uum; volume,  2100. 
The  equivalents  for 
each  cylinder  of  the 
combined  power  of 
both  are  as  follows: 
For  the  high-press- 
ure cylinder,  43125 
+  43-64  =  86-765. 
For  the  low-pressure 
cylindsr,   14*25  -f- 
14082  =  28*332. 
From  these  data,  the 
calculation    of  the 
theoretical  rates  of 
water  consumption 
will  be  for  each  cyl- 
inder as  follows:  For 
the  high-pressure 

y  ,  859-375 
^^^^^'^''8^765X550 
=  18  lbs.  per  indi- 
cated horse-power 
per  hour.  For  the 
low-pressure  cylin- 
der 859*375 


28-332  X  2100  ~~ 
14*44  lbs.  indicated 
horse-power  per 
hour. 

The  maximum  compression-pressures  of  each  are  so  nearly 

equal  to  the  terminal,  that  no  correction  for  clearance  and  cushion 
need  be  made.    The  diagrams  indicate  good  performance  in  all 


Diagram  No 


308  THB  ENGINEER'S  HANDY-BOOK. 

respects,  tl^  lack  of  smoothness  in  the  lines  being  presumably 
due  to  the  tremulous  motion  of  the  vessel. 


Diagrams  No.  21. 


Diagrams  No.  21  were  taken  from  the  simple  surface-condensing 
engine  of  the  steamship  Vera  Cruz,  of  Alexander's  Line,  on  her 


THE   ENGINEER'S  HANDY-BOOK. 


309 


thirty-ninth  voyage  from  New  York  to  Havana.  Diameter  of 
cylinder,  48^  inches ;  stroke,  6  feet ;  speed,  60  revolutions,  or  720 
feet  per  minute;  scale,  30  lbs.  per  inch.  The  boiler-pressure,  which 
is  represented  by  the  lines  above  the  diagram,  was  72  lbs.  per 
square  inch ;  vacuum,  23  inches,  the  equivalent  of  which  is  rep- 
resented by  the  dotted  line  V  V.  The  full  line  below  represents 
a  perfect  vacuum.  The  theoretical  expansion  curves  are  the  adia- 
batic  curves,  calculated  from  the  table  of  volumes  on  pages  39 
and  43  of  Roper's  Hand-Book  of  Land  and  Marine  Engines.  The 
calculations  are  as  follows : 

Assuming  the  clearance  to  be  5  per  cent.,  the  mean-pressure  of 
the  theoretical  diagram  around  the  diagram  B,  which  is  based  on 
the  line  V  F,  will  be  32*8  lbs.  The  mean  effective  pressure  of 
actual  diagram  jB,  28*5  lbs.  Percentage  realized  of  the  full  theo- 
retical value  of  the  boiler,  terminal,  and  condenser  pressures, 
28*5  X  100 

— ^^Tg  —  86'88.  Parallel  calculations  for  the  diagram  T  give 

the  following : 

Mean-pressure  of  theoretical  diagram,  .  .  .  31*8  lbs. 
Mean  effective  pressure  of  actual  diagram,       .       .  27*25  lbs. 

Percentage  realized,     ^f-,^        =  85*68. 

The  mean  of  both  ends  is  as  follows : 

Mean-pressure  of  theoretical  diagrams,     .       .  .    32*3  lbs. 

Mean  effective  pressure  of  actual  diagrams,   .  .  27*875  lbs. 

Percentage  realized,     ^qo.q        =  86*3. 

The  area  of  the  cylinder  being  1847*45,  and  the  piston  speed 
720  feet  per  minute,  the  horse-power  value,  or  the  horse-power  for 
each  pound  of  mean  effective  pressure,  is  calculated  as  follows : 
1847*45  X  720 

 33000  ~  "^^^  mean  effective  pressure  being  27,875 

lbs.,  the  total  horse-power  is  27,875  x  40*3  =  1123*36.  The  ter^ 
minal-pressure  is  13  lbs.,  the  volume  of  which  is  1842,  and  the 


310 


THE   engineer's  HANDY-BOOK. 


leoretical  rate  of  water  consumption  will  be  found  as  follows ; 
1842^X^27-875  ~  ^^'^^       P^^  indicated  horse-power  per  hour. 

The  compression-pressure  so  nearly  equals  the  terminal,  that 
no  correction  for  compression  and  clearance  is  necessary.  The  dia- 
grams are  in  nearly  all  respects  excellent;  the  curves,  allowing 
for  the  unsteadiness  which  is  apt  to  characterize  diagrams  taken 
from  ocean-steamship  engines,  are  remarkably  correct ;  the  engine 
was  fitted  with  Corliss  valves.  The  difference  of  about  2^  lbs. 
between  the  vacuum  attained  in  the  condenser,  V  V,  and  that  at- 
tained in  the  cylinder  is  a  circumstance  which  is  almost  insepa- 
rable from  such  a  Jiigh  piston  speed.  A  comparison  of  the  rate  of 
water  consumption  with  that  of  such  others  as  have  been  cal- 
culated, will  be  instructive,  particularly  with  reference  to  the  rel- 
ative economic  merits  of  simple  and  compound  engines,  a  question 
which  is  yet  unsettled.  A  comparison  of  the  foregoing  calculation 
with  the  ordinary  or  long  process  will  be  instructive,  as  showing 
the  correctness  of  the  short  method  and  the  vast  amount  of  labor 
saved  by  it,  especially  when  dealing  with  large  engines. 

Thus,  720  feet  per  minute  x  60  x  12  —  518,400  inches  per  hour, 
which,  multiplied  by  1847-45,  (area  of  piston,)  =  957,718,080  cubic 
inches  per  hour,  as  the  displacement  of  the  engine. 

Then,  957,718,080     27*648  (cubic  inches  of  water  per  pound) 

1842  (volume  of  13  lbs.  terminal)  =  18,805*476  lbs.  of  water 
as  its  total  theoretical  consumption  of  water  per  hour ;  this  -r- 
1123*36  (the  indicated  horse-power)  =  16*74  lbs.  per  indicated 
horse-power  per  hour,  as  before. 

In  making  a  complete  analysis  of  diagrams,  a  statement  of  the 
mean  effective  pressure,  exclusive  of  vacuum  and  that  due  to  the 
vacuum,  ought  to  be  given  separately.    Thus : 

Mean-pressure,  exclusive  of  vacuum,    .       .       .    19'375  lbs. 
Mean-pressure  due  to  vacuum,        ....     8*5  lbs. 
Percentage  of  power  due  to  vacuum,  •     •       .       .  30*5. 


THE  engineer's  HANDY-BOOK. 


311 


Diagrams  No.  22  were  taken  from  the  same  engine  as  diagram 
No.  21,  on  the 
steamer's  forty- 
fourth  return  voy- 
age to  New  York 
from  Havana.  It 
represents  con- 
siderably lighter 
load  than  diagram 
No.  21,  and  shows 
the  attainment  of 
a  better  vacuum, 
is  more  perfect  in 
its  lines,  and  is 
equally  correct 
in  its  expansion 
curves.  The  line 
above  the  dia- 
grams represents 
the  boiler-press- 
ure. The  calcu- 
lations are  as  fol- 
lows: Mean  ef- 
fective pressure 
of  diagram  B,  17 
lbs.  Mean  effec- 
tive pressure  of 
diagram  T,  19*5 
lbs.   Mean  of  the 

two,  18*25  lbs.  Diagrams  No.  22. 

Terminal-pressure  of  bottom  diagram,       .       .       .6*  lbs. 

Terminal-pressure  of  top  diagram,     .       .       .       .7*  lbs. 

Mean  of  the  two,  6*5  lbs. 

Taking  3600  as  approximately  the  volume  of  6*5  lbs.  pressure, 
the  rate  of  water  consumption  will  be  13*08  lbs.  per  indicated 


312 


THE   engineer's  HANDY-BOOK. 


horse-power  per  hour^  which,  if  equalled,  has  never  been  exceeded 
by  any  other  engines  in  this  country,  either  simple  or  compound. 

Diagrams  Nos.  23  and  24  were  taken  from  the  simple  surface- 
condensing  engines  of  the  steamship  Knickerbocker,  of  Crom- 


T 


Diagram  No.  23. 

well's  line,  and  running  between  New  York  and  Boston.  Many 
of  the  conditions  could  not  be  ascertained,  but  the  mean  effective 


Diagram  No.  24. 


pressure  of  B  appears  to  be  about  29  lbs.,  and  of  T,  19  lbs.  The 
calculations  of  the  rate  of  water  consumption  give  for  the  card, 
By  13-74  lbs.,  and  for  T,  15-55.  These  very  low  rates  are  to  some 
extent  due  to  the  very  perfect  vacuum  attained.    With  the  excep 


THE   ENGINEER'S  HANDY-BOOK. 


313 


tion  of  the  tardy  inductioD,  or  deficient  lead,  as  indicated  by  the 
inward  inclination  of  the  induction  line,  and  the  great  difference 
in  the  work  represented  by  the  two,  they  are  very  perfect.  And 
since  both  features  may  have  been  purposely  introduced,  the 
former  to  secure  smooth  running  and  the  latter  to  compensate  for 
unbalanced  weight,  etc.,  they  should  not  be  hastily  pronounced 
faults  of  adjustment. 

Diagrams  No.  25  present  a  case  of  extremely  difficult  analysis, 
us  none  of  the  conditions  under  which  they  were  taken  could  be 


Diagrams  No.  25. 


ascertained.  The  left  hand  one  shows  tardy  induction,  by  the  in- 
clination of  the  admission  line  to  the  right.  From  A  to  D,  as 
will  be  observed,  the  pressure  falls  considerably ;  but  it  does  not 
appear  that  the  cut-off*  has  taken  place,  as  the  curvature  of  the 
line  is  upward,  which  is  never  the  case  with  a  true  expansion 
curve.  From  D  to  E,  it  will  be  seen,  the  pressure  rises  slightly, 
which  renders  it  evident  that  the  steam  cannot  have  been  cut  off* 
at  any  point  previous  to  E,  unless  for  an  instant,  after  which  it 
was  readmitted.  Supposing  the  line  to  correctly  represent  the 
27 


314 


THE   ENGINEER'S  HANDY-BOOK. 


actual  pressure  on  the  piston,  the  most  probable  cause  of  the  rise 
in  the  curve  is,  that  the  steam  was  admitted  during  the  entire 
stroke  to  but  not  with  sufficient  freedom  to  maintain  the  press- 
ure when  the  piston  travel  was  greatest,  or  that  the  connecting- 
pipe  between  the  cylinder  and  the  indicator  was  long  and  tortuous. 
The  right  hand  diagram  is  not  so  peculiar,  as  it  shows  a  hori- 
zontal steam-line  and  a  tolerably  well  defined  point  of  cut-off,  C, 
and  expansion  curve.  In  both  the  exhaust  is  much  more  free  and 
prompt  than  the  induction.  The  best  vacuum  was  obtained  at 
the  beginning  of  the  return  stroke,  F  F,  after  which  the  lines 
undulate  in  a  manner  not  easily  accounted  for,  without  an  inti- 
mate knowledge  of  the  construction  of  the  engine  and  the  con- 
ditions attending  it. 

Diagrams  Nos.  26  and  27  were  taken  from  the  simple  condensing 
engi  ne  of  the  steamboat  Mary  Powell,  plying  between  New  York  city 
and  Albany,  which  has  exceeded  in  point  of  speed  any  other  steam 
craft  on  American  waters,  or  in  Europe,  so  far  as  can  be  ascertained, 
making  25  miles  per  hour  between  those  points  with  perfect  ease. 

Diameter  of  cylinder,  72  in. 

Stroke  of  piston,  12  ft. 

Diameter  of  piston-rod,    .       .       .       .       .       .     8  in. 

Diameter  of  air-pump,  40  in. 

Stroke  of  the  air-pump,  62  in. 

Very  few  data  could  be  ascertained,  but  it  seems  that  the  M.  E. 
p.  of  the  top  diagram  was      .....    22*02  lbs. 

Of  the  bottom,   22-23 

Mean  of  both,  22-13  " 

Terminal  of  top,  13-5  " 

Of  bottom,  18-  " 

Mean  of  both,  15-75  " 

Theoretical  clearance  of  top,      .       .       .       .12  per  cent. 
Theoretical  clearance  of  bottom,     .       .       .       17    "  " 
The  water  consumption  appeared  to  be  about  24-62  lbs.  per 
horse-power  per  hour.    The  bottom  card  has  the  more  compres- 
sion.   The  size  and  speed  of  the  engine  could  not  be  ascertained. 


THE  engineer's  HANDY-BOOK. 


315 


The  Powell  is  a  splendid  specimen  of  the  American  beam-en- 
gine river^boat  which  some  years  ago  were  so  great  favorites  on 


Diagram  No.  26. 


Diagram  No.  27. 


account  of  the  great  speed  they  were  capable  of  developing,  but 
which  are  fast  disappearing,  and  being  superseded  by  another  class 
of  engines,  on  account  of  inherent  defects  in  their  arrangement 


316 


THE   ENGINEER'S  HANDY-BOOK. 


Formula  for  Finding  the  Theoretical  Clearance  when 
the  Scale  is  known. 

From  two  points  in  the  expansion  curve,  as  A  B,  the  former 
as  early  and  the  latter  as  late  as  possible  consistent  with  the  cer- 
tainty that  both 
are  in  the  expan- 
sion curve,  draw 
the  vertical  lines, 
A  Daud  B  C,  at 
right  angles  to 
the  atmospheric 
and  vacuum  lines 
and  the  horizon- 
tal lines,  J.  Cand 
B  D,  forming  the 
parallelogram,  A 
C  D  B.  Then, 
through  C  D 
draw  a  diagonal 
line,  continuing 
it  downwards  till 
it  intersects  the 
vacuum  line  at 
and  from  this 
point  draw  a  ver- 
tical line,  which 
will  represent  the 
clearance.  It  will, 
in  the  majority 
of  cases,  indicate 
more  clearance 
than  actually  ex- 
Diagram  No.  28.  ists;  but  if,  as  is 
sometimes  the  case  with  large  engines  of  good  construction  and 


THE  engineer's  HANBY-BOOK. 


317 


in  good  condition,  the  diagram  agrees  closely  with  exact  theory, 
the  clearance  thus  shown  will  be  less  than  the  actual. 

On  theoretical  grounds,  there  should  be  no  clearance  at  all,  as 
any  space  between  the  cylinder-head  and  the  piston  at  the  end  of 
the  stroke  must  be  filled  with  steam.  But  in  practice  it  is  impos- 
sible to  dispense  with  it,  since  any  wear  of  the  parts  must  alter 
the  stroke,  and  foreign  substances,  such  as  grease  or  water,  may 
find  their  way  into  the  cylinder.  The  loss  resulting  from  clearance 
in  cylinders  may  be  lessened  by  judicious  design,  since,  if  com- 
pression takes  place  as  the  piston  approaches  the  end  of  its  stroke, 
it  serves  to  raise  the  temperature  of  the  steam  enclosed,  reduces 
the  quantity  of  new  steam  required,  and  brings  the  raomentun: 
of  the  piston  to  rest,  thereby  lessening  the  shock  on  the  crank. 

Formula  for  Finding  the  Scale  of  a  Diagram  when  the 
Clearance  is  hnown. 

Draw  a  line  representing  the  clearance  ;  then  proceed,  as  before, 
to  draw  the  parallelogram,  A  C  D  B,  and  continue  its  diagonal, 
C  D,  till  it  intersects  the  clearance  line,  as  at  E,  From  the  near- 
est point  to  this  point  of  intersection,  generally  below,  (which,  by 
its  distance  from  the  atmospheric  line,  will  represent  the  pressure 
of  the  atmosphere,  according  to  one  of  the  scales  in  use,)  draw 
the  vacuum  line  which  fixes  the  scale.  For  instance,  suppose  the 
intersection  occurs  about  of  an  inch  below  the  atmospheric 
line.  The  nearest  point  below  that  point  at  which  a  vacuum  line 
can  be  located  to  correspond  with  any  of  the  usual  scales  is  that 
corresponding  with  the  30  lbs.  scale,  or  a  little  less  than  ^  inch. 
If,  however,  there  be  reason  to  suspect  that  the  actual  scale  varies 
from  30  to  40,  (32,  for  instance,)  this  method  will  not  determine 
it  with  certainty,  but  it  will  approximate  it  when  the  diflferent 
scales  used  are  known  to  differ  from  each  other  to  the  extent  of 
10  to  20  lbs.  per  inch.  No  method  can  be  relied  upon  when  only 
a  limited  length  of  the  expansion  curve  is  available,  or  when  it  is 
much  distorted  by  vibration,  or  other  defects  in  the  performance 
of  the  instrument. 
27* 


318         THE  engineer's  handy-book. 

Formulcefor  Finding  the  Horse-Fower  of  Steant" Engines 
by  Indicator  Diagrams. 

The  custom  of  dividing  the  indicator  card  into  ten  ordinates 
has  been  generally  adopted  by  engineers  because  ten  is  the  most 


Diagram  No.  29. 


convenient  number  for  a  divisor,  since  the  process  of  dividing  by 
it  consists  merely  of  pointing  off  one  decimal.  The  M.  E-  P.  is 
ascertained  by  dividing  the  aggregate  length  of  the  ordinates  by 
their  number,  and  multiplying  the  quotient  by  the  scale  of  the 
diagram.  The  following  instructions  will  be  found  useful  to  per- 
sons unaccustomed  to  make  the  calculation. 

First.  — Divide  the  card  into  ten  equal  parts,  as  shown  by  the 
dotted  lines  in  the  above  diagram,  after  which  draw  a  line  exactly 
through  the  centre  of  each  space,  as  shown  by  the  full  lines  1,  2, 
3,  etc.  Then  draw  the  dotted  line  A  A,  representing  the  atmos- 
pheric line,  also  draw  the  full  line  V  V,  representing  the  zero,  or 
vacuum  line,  which  is  equal  to  14y\  pounds,  below  the  atmos- 
pheric line ;  then  measure  the  card  at  the  following  points : 


THE   engineer's   HANDY-BOOK.  319 


The  initial-pressure  as  shown  at  /. 

The  pressure  at  the  point  of  cut-off  .       .       •  .CO. 

The  terminal-pressure  at  T. 

The  pressure  at  the  end  of  the  cushion      ...  (7. 


Next  measure  the  full  lines,  or  ordinates  1,  2,  3,  etc.,  with  a 
slip  of  paper,  marking  with  a  sharp  pencil  or  the  point  of  a  knife 
the  length  of  each,  until  it  contains  the  sum  of  all  their  lengths^ 
which  in  this  case  will  be  found  to  be  11*75  inches;  then,  from 
11*75 

the  mean  length  —  1*175  inches,  and  the  mean-pressure 
1*175  X  16  scale  of  the  indicator  =  18*80  pounds;  the  correct 


rendering  of  a  card  would  be  as  follows : 


Initial-pressure,     (above  zero) 

=   /.  = 

32-OIbs. 

Pressure  at  cut-off      "  " 

=  G  0.  = 

28-0  " 

Terminal-pressure      "  " 

=    T.  = 

17-0  " 

Mean  back-pressure    "  " 

=   B.  = 

5-6  " 

Pressure  at  end  of  cushion  (above  zero) 

=  a  = 

18-5  " 

Mean-pressure 

18-8  "  • 

Suppose  the  diagram  to  be  taken  from 

one  end  of 

a  cylinder 

50  inches  in  diameter  (with  a  stroke  of  48  inches),  making  50 


revolutions  per  minute,  and  the  area  of  piston  to  be  1963*5  square 
inches,  then  1963*5  X  18*8  —  36,913*8.  This  pressure  acts  on 
the  piston  throughout  the  stroke,  48  inches,  50  times  a  minute, 
and  the  work  done  on  one  side  of  the  piston  in  each  minute  would 
48 

be  36,913*8 x50x^  =  7,382,760.  Now,  if  another  diagram  were 

taken  from  the  other  end  of  the  cylinder,  and  the  measurements 
be  the  same,  the  total  work  done  by  the  engine  each  minute  would 
be  3000  =  447,  indicated  horse-power. 

Another  Formula. 

In  the  analysis  of  diagrams  in  this  work,  the  usual  custom  of 
dividing  the  diagram  into  ten  ordinates  has  been  departed  from, 
because,  in  the  first  place,  ten  ordinates  were  not  considered  enough 
to  insure  accurate  calculation ;  and,  secondly,  because,  when  the 


320 


THE  engineer's  HANDY-BOOR. 


number  of  ordinates  is  made  the  same,  or  one-half,  one-third,  or 
one-fourth  as  many  as  there  are  pounds  per  inch  in  the  scale 
of  the  diagram,  the  calculation  is,  if  anything,  simpler  than  the 
old  process,  since  the  sum  of  the  ordinates,  as  measured  on  the 
strip  of  paper  in  inches,  is  the  mean  effective  pressure  at  once, 
when  the  number  of  ordinates  equals  the  scale,  and  in  other  cases 
it  bears  the  same  relation  to  it  that  the  number  of  ordinates  does 
to  the  scale.  Ten  ordinates  may  be  used,  however,  for  such  scales 
as  are  divisible  by  10. 

Suppose  the  scale  to  be  60,  and  the  number  of  ordinates  10, 
and  that  the  sum  of  their  lengths  is  7  inches.  According  to  the 
former  process,  -^^  =  -7  X  60  =  42  lbs. ;  by  the  latter  method,  sup- 
posing the  number  of  ordinates  to  be  J  of  the  scale,  the  process  is 
simply  6  X  7  =  42 ;  that  is,  the  mean  effective  pressure  would  be 
six  times  the  sum  of  the  length  of  the  ordinates,  if  the  scale  is  six 
times  their  number. 


Diagram  No.  30. 


Suppose  the  scale  to  be  40  lbs  per  inch,  one-half  of  that  num- 
ber, or  20  ordinates,  as  shown  in  the  above  diagram,  are  used ; 
and  suppose  the  sum  of  their  lengths  is  found  by  the  process  of 
measurement  above  given  to  be  15*3  inches,  then  twice  that  num- 
ber will  be  the  mean  effective  pressure  in  pounds  per  square  inch, 
or  15*3x2  =  30*6  lbs.    Suppose  the  cylinder  of  an  engine  is  20 


THE   engineer's  HANDY-ROOK. 


321 


inches  in  diameter,  40  inch  stroke,  running  at  a  speed  of  75  revo- 
lutions, or  500  feet  per  minute;  the  area  of  such  a  piston  would 

be  314*16  square  inches;  hence,  ^^^^^^  =  4*727  horse-power 

for  each  pound  of  mean  effective  pressure.  The  latter  being  30*6, 
then  30*6  X  4*727  =  145,656,  the  indicated  horse-power. 

What  Indicator  Diagrams  Show,  and  How  they  Show  it. 

The  object  of  indicator  diagrams  is  to  show  the  pressure  acting 
on  the  piston  of  the  engine  to  which  it  is  applied  at  all  points,  and 
also  at  what  part  of  the  stroke  any  change  of  pressure  takes  place. 

Indicator  diagrams  supply  the  means  by  which  to  calculate  the 
mean  effective  pressure  acting  on  the  piston,  which,  together  with 
the  known  area  and  speed  of  the  piston,  furnishes  the  factors  from 
which  to  calculate  the  power  of  engines. 

Indicator  diagrams  show  the  steam-pressure  by  the  height  to 
which  the  pencil  traces  the  line  on  the  paper  measured  from  the 
atmospheric  or  vacuum  line. 

When  the  line  representing  the  back-pressure  in  the  diagrams 
of  high-pressure  engines  shows  more  than  one  pound  above  atmos- 
phere, or,  in  low-pressure  engines,  two  or  three  pounds  more  than 
the  vacuum-gauge  shows  in  the  condenser,  the  diagram  indicates 
undue  back-pressure,  and  that  there  is  evidently  something  wrong. 

The  diagram  shows  whether  the  valves  of  a  steam-engine  are 
properly  set  or  not,  because,  if  there  is  too  little  lead,  it  will  lean 
towards  the  exhaust.  If  the  exhaust  takes  place  too  early,  the 
point,  i),  in  diagram  No.  1,  page  291,  will  be  further  from  the  end, 
/;  whereas,  if  the  exhaust  closes  too  early,  and,  as  a  consequence, 
there  is  too  much  "  cushion  "  or  "  compression,''  it  will  be  shown 
by  the  great  distance  of  the  point  F  from  E, 

A  diagram  shows  whether  the  piston  and  valves  are  leaky  or 
not ;  though  it  is  often  difficult  to  decide  to  which  the  leakage  may 
be  due,  as  the  one  neutralizes  the  other.  But  if  the  piston  alone 
leaks,  the  effect  will  be  a  more  rapid  fall  of  the  pressure  during 

V 


322 


THE   engineer's  HANDY-BOOK. 


expansion  than  theory  requires,  and  the  back-pressure  will  be 
greater  than  if  the  piston  was  tight.  If  the  slide-valve  leaks,  the 
effect  on  the  diagram  will  depend  on  the  point  at  which  the  leak- 
age occurs.  It  may  leak  at  the  ends,  so  as  to  keep  on  admitting 
steam  after  it  covers  the  port ;  or  it  may  leak  at  the  bridges,  and 
allow  the  steam  to  escape  in  advance  of  the  exhaust.  In  the  first 
case,  the  expansion  line  would  fall  less,  and  in  the  latter  case 
more,  than  theory  requires. 

A  diagram  shows  whether  the  steam  is  throttled  or  not  by  the 
expansion  curve  falling  below  the  boiler-pressure  when  the  throttle- 
valve  is  wide  open. 

A  diagram  shows  the  effect  of  small  ports  and  small  steam  con- 
nections by  the  steam-line  starting  below  boiler-pressure,  and  fall- 
ing before  the  closing  of  the  cut-off.  A  pipe-diagram  is  the  only 
'  reliable  means  of  determining  such  defects. 

A  diagram  shows  the  effect  of  exhaust-lead,  by  the  exhaust 
taking  place  before  the  end  of  the  stroke  is  reached,  as  in  nearly 
all  the  diagrams  shown. 

A  diagram  shows  that  the  indicator  is  out  of  order,  or  whether 
there  is  lost  motion  between  the  piston  and  the  pencil  lever,  by 
indicating  more  back-pressure  than  actually  exists. 

A  diagr^  shows  the  point  of  cut-off,  which  may  be  termed 
the  point  of  contrary  flexure,  that  is,  the  point  where  the  steam- 
line,  B  C,  (explanatory  diagram)  changes  its  direction  from  a 
straight  line  to  a  curve. 

A  diagram  shows  the  state  of  the  vacuum  in  the  condenser,  and 
whether  too  much  or  too  little  injection-water  is  used  or  not;  but 
in  this  case  it  is  less  reliable  than  the  vacuum-gauge.  Too  much 
injection-water  can  only  be  shown  on  the  diagrams,  by  taking  one 
first  with  the  proper  quantity,  and  another  with  the  increased 
quantity,  and  calculating  the  power  of  each.  If  the  extra  power, 
required  to  pump  out  the  extra  water  against  the  atmospheric 
pressure,  more  than  counterbalanced  the  gain  from  the  better 
vacuum,  the  conclusion  would  be  that  too  much  injection- water 
was  used. 


THE   ENaiNEER's  HANDY-BOOK. 


323 


The  Planimeter.* 

The  planimetep,  though  not  a  receut  invention,  is  almost  un- 
known among  engineers  on  this  continent.  This  arises  from  the 
fact  that,  after  its  invention  by  Amsler,  certain  Swiss  and  German 
engineers  got  control 
of  it,  and  limited  the 
number  that  should 
be  manufactured  to 
their  own  individual 
necessities.  It  has 
never  been  manufac- 
tured in  this  country, 
or  even  offered  for 
sale,  until  quite  re- 
cently. Its  functions 
are  to  measure  indi- 
cator diagrams,  ir- 
regular flues,  steam 
passages,  and  all  dif- 
ficult or  intricate  fig- 
ures. It  gives  at 
once  the  area  of  a 
figure,  without  any 
second  measurement 
being  required,  as  the 
reading  shown  on  the 
index  counter  gives  the  accurate  area  in  square  inches  of  the  dia- 
gram over  which  it  had  been  passed. 

To  use  the  instrument,  fasten  the  figure  to  be  measured  on  a 
smooth  board,  and  insert  the  point.  A,  in  the  board  at  any  con- 
venient location ;  then  make  a  mark  on  the  diagram,  as  at  D ; 
next  fix  the  movable  point,  at  the  place  selected  for  starting ; 
then  turn  the  index-roller,  Q  round  until  0,  on  its  periphery, 
corresponds  with  the  0  on  the  fixed  vernier ;  then  move  it  round 

*  See  page  656. 


324         THE  engineer's  handy-book. 

the  figure  to  the  right,  or  in  the  direction  of  the  hands  of  a  watch* 
After  it  passes  round  the  entire  figure,  note  how  many  whole 
numbers  and  subdivisions  have  passed  the  0  on  the  vernier.  The 
whole  numbers  will  indicate  the  square  inches,  and  the  subdivisions 
tenths  of  square  inches.  If  the  0  on  the  vernier  falls  between 
two  subdivisions  marked  on  the  roller,  read  the  number  of  square 
inches  and  tenths;  then  look  on  the  vernier  from  0  to  10,  and  find 
a  mark  which  coincides  with  one  on  the  rollers ;  the  number  of 
such  mark,  counting  from  0,  will  be  the  hundredths  or  second 
decimal  place. 

Thus  suppose  that,  in  the  figure  measured,  six  subdivisions  and 
part  of  another  one  have  passed,  and  that  the  fourth  mark  on  the 
vernier  coincides  with  a  mark  on  the  roller,  the  area  of  the  figure 
will  be  either  3*64,  13*64,  or  23*64  square  inches,  according  to 
whether  the  roller  has  made  less  than  one,  more  than  one,  and 
less  than  two,  or  between  two  and  three  revolutions.  The  eye 
can  readily  decide  as  to  the  number  of  revolutions  the  roller  has 
made,  as  it  would  be  impossible  to  make  a  mistake  of  ten  square 
inches  in  estimating  the  area  of  a  figure  within  the  capacity  of 
^he  instrument.  If  the  figure  measured  is  an  indicator  diagram, 
it  will  nearly  always  be  of  less  area  than  ten  square  inches,  or  at 
most  only  a  trifle  more,  as  the  utmost  capacity  of  the  indicator  is 
5|  by  2|  inches,  or  15|-  square  inches ;  and  they  are  very  seldom 
worked  beyond  4  by  2^  inches. 

To  find  the  mean  effective  pressure  of  a  diagram  from  its  area: 
Multiply  the  area  by  the  scale,  and  divide  the  product  by  the 
length  of  the  diagram  in  inches.  Or  divide  the  area  by  the  length 
of  the  diagram,  and  multiply  the  quotient  by  the  scale.  The 
product  is  the  mean  effective  pressure. 

Example. — Suppose  the  area  is  found  as  above  to  be  3*64  square 
inches,  the  scale  40,  and  the  length  of  the  diagram  is  3|  (3*875) 
inches ;  3*64  x  40  H-  3*875  =  37*65  lbs.,  or  3*64  -r-  3*875  x  40  = 
37*65  lbs. 

It  will  be  seen  that  the  labor  of  calculation  will  be  facilitated, 
if,  in  taking  the  diagrams,  care  is  taken  to  make  them  even  inches 


THE   engineer's  HANDY-BOOK. 


325 


in  length.  But  as  the  engineer  will  have  to  measure  many  not 
of  his  own  taking,  he  should  have  a  rule  divided  into  hun- 
dredths. 

The  annexed  diagram  was  measured  by  the  planimeter,  and 
gives  the  following  results:  Area,  1*34  square  inches;  1*34  multi- 
plied by  40  the  scale  -r- 1-98  =  18,  the  M.  E.  P. 


The  area  of  a  figure  may  be  taken  without  placing  the  0  on 
the  roller  opposite  the  0  on  the  vernier;  but  in  such  cases  it  is 
necessary  to  take  the  reading  before  and  after  the  tracing  is  made ; 
the  difierence  between  the  two  readings  will  be  the  area  of  the 
figure.  But  it  is  preferable  to  place  the  O's  together.  The  mov- 
able point  of  the  instrument  may  also  be  turned  to  the  left,  but 
in  this  case  the  reading  must  be  subtracted  from  10  to  give  the 
true  reading.  Each  of  the  figures  stamped  on  the  roller  indicates 
a  square  inch  of  area,  and  if  a  figure  contains  10  square  inches? 
at  the  tracing-point,  the  roller  will  revolve  once,  and  the  O's  will 
coincide  as  at  the  start. 

Steam-Engiiie  Economy. 

Hardly  a  "decade"  has  passed  since  the  days  of  Newcomen, 
which  has  not  witnessed  the  promulgation  of  some  vague  scheme 
which  it  was  claimed  would  revolutionize  the  economical  working 
of  the  steam-engine,  or  even  do  away  with  it  entirely,  and  super- 
28 


326  THE   ENGINEER'S  HANDY-BOOK. 


sede  it  by  something  else.  Such  wild  schemes  have  invariably- 
proved  failures,  as  they  must  ever  do,  because  there  are  some 
principles  involved  in  the  working  of  the  steam-engine  which,  ac- 
cording to  the  natural  order  of  things,  can  never  be  disproved. 
Consequently,  those  who  intend  to  purchase  steam-engines,  or  those 
who  have  capital  invested  in  them,  need  entertain  no  fears  that 
steam  as  a  motive-power,  and  the  steam-engine  as  a  motor,  will 
ever  be  superseded  by  anything  else,  while  efficiency  and  economy 
are  desirable  objects  to  be  attained. 

Nor  has  there  been  any  new  principle  discovered  in  connection 
with  the  steam-engine  since  "  Newcomen's  "  time,  as  Watt,  Horn- 
blower,  and  Oliver  Evans  knew  just  as  much  about  the  latent 
and  sensible  heat,  temperature,  and  the  elastic  force  of  steam  as  we 
do ;  though  they  lacked  the  knowledge  of  applying  it  so  econom- 
ically to  the  piston.  This  did  not  arise  from  ignorance  of  its 
properties  so  much  as  from  the  want  of  proper  facilities  to  apply 
it.  Nor  is  it  at  all  likely  that  the  steam-engine  of  the  present 
day  will  ever  be  much  improved  upon  in  point  of  economy  or 
efficiency,  though  it  may  be  in  point  of  durability.  Good  ma- 
terial, good  tools,  and  perfect  workmanship  will  go  far  towards 
the  economical  working  of  the  steam-engine.  It  is  a  very  notice- 
able fact,  that  no  important  improvement  has  been  made  in  steam- 
engines  of  any  kind  within  the  past  15  years.  To  be  sure,  there 
have  been  many  innovations  introduced  in  that  time,  but  upon  ex« 
amination  it  will  be  discovered  that,  in  nearly  all  cases,  they  were 
a  revamp  of  things  which  had  been  used  before,  and  abandoned  for 
want  of  experience  in  their  use  and  proper  facilities  for  perfect- 
ing them.  * 

The  mean  effective  pressure  on  the  piston  of  a  steam-engine  is 
the  exponent  of  the  work  performed.  The  term  effective  press- 
ure" means  the  amount  by  which  the  total  pressure  behind  the 
piston  exceeds  that  which  acts  on  the  other  side  in  opposition  to 
its  movement.  The  <6rmina/-pressure,  or  that  at  which  the  steam 
is  released  from  the  cylinder,  is  the  corresponding  exponent  of  the 
consumption  of  water  by  the  engine  or  the  cost  of  the  power. 


THE   engineer's  HANDY-BOOK. 


327 


Hence,  the  best  economy  is  attained  when  the  mean  effective  press- 
ure is  highest  relatively  to  the  <ermma/-pressure,  and  anything 
that  will  increase  the  former  without  correspondingly  increasing 
the  latter,  or  which  will  diminish  the  latter  without  correspond- 
ingly diminishing  the  former,  will  improve  the  economy. 

The  amount  of  water  consumed  by  an  engine  is  the  only  in- 
telligible criterion  of  the  economical  results  it  is  capable  of  pro- 
ducing. The  amount  of  fuel  consumed  will  depend  upon  the 
kind  of  boiler  used,  its  condition  as  to  dirt,  scale,  etc.,  the  manner 
in  which  it  is  set  and  fired,  the  quality  of  fuel  used,  the  draught,  and 
numerous  other  conditions ;  while  the  amount  of  water  used  will 
depend  entirely  on  the  engine,  provided  that  it  is  furnished  with 
dry  steam.  The  theoretical  rate  of  water  consumption,  as  deduced 
from  the  diagrams,  can  never  be  realized  in  practice.  A  certain 
amount  will  always  be  lost  from  condensation,  leakage,  and  un- 
evaporated  spray  in  the  steam,  for  which  no  process  of  calculation 
can  make  allowance. 

Now  admitting  that  the  evaporative  efficiency  of  steam-boilers, 
under  the  best  conditions,  is  8  pounds  of  water  per  pound  of  coal, 
providing  the  water  consumption  of  an  inferior  type  of  engine  is 
one  cubic  foot,  or  62A  lbs.,  it  would  require  7|  lbs.  of  coal,  or  its 
equivalent  in  other  fuel,  to  develop  a  horse-power;  while  an  auto- 
matic cut-ofi*  engine  would  yield  a  horse-power  with  a  water  con- 
sumption of  20  lbs.,  and  the  consumption  of  less  than  3  lbs.  of 
good  coal.  If  an  inferior  type  of  engine  require  the  consumption 
of  5  lbs.  of  coal  pei-  horse-power  per  hour,  and  an  improved 
engine  produce  the  same  power  from  a  consumption  of  3  lbs.,  the 
latter  will  effect  a  saving  of  40  per  cent,  in  fuel  over  the  former. 
Such  comparisons  may  be  considered  extreme,  but  this  is  not  the 
fact,  as  such  cases  are  quite  common  in  every  manufacturing  dis- 
trict. A  manufacturer  at  Detroit,  Michigan,  was  induced  .to  take 
out  an  engine,  which  he  was  influenced  to  believe  was  wasteful, 
and  replace  it  with  one  that  was  represented  to  be  very  powerful 
and  economical,  and  at  the  same  time  very  cheap.  The  engine 
was  represented  by  the  manufacturers  as  being  capable  of  de- 


328 


THE   engineer's  HANDY-BOOK. 


veloping  100  horse-power ;  but  it  utterly  failed  to  come  up  to  this 
representation.  When  the  indicator  was  applied,  it  showed  that 
the  engine  was  developing  only  60  horse-power.  The  coal  con- 
sumption was  found  to  be  nearly  8  pounds  per  horse-power  per  hour. 

The  great  Lancashire  (England)  strike  which  occurred  during 
the  present  year,  and  resulted  in  a  loss  to  both  employers  and  em- 
ployees of  several  millions  of  pounds  sterling,  was  brought  about 
by  an  attempt  on  the  part  of  the  manufacturers  to  reduce  the 
wages  of  the  operatives  one  cent  on  every  ten  yards  of  manufac- 
tured cloth.  They  defended  their  action  on  the  ground  that  ten 
per  cent,  was  all  the  profit  they  realized  on  their  manufactured 
goods,  and  stated  that,  unless  the  operatives  would  submit  to  the 
reduction,  they  would  have  to  discontinue  their  business.  Never- 
theless, it  had  been  well  known  for  years,  by  reports  made  to  the 
Lancashire  Institute  and  the  officers  of  the  Midland  Steam-Users 
Association,  that  there  were  thousands  of  steam-engines  in  that 
county,  supplying  power  to  factories,  that  were  consuming  from 
eight  to  nine,  and  in  some  cases  ten  and  a  half,  pounds  of  coal  per 
horse-power  per  hour,  and  yet  the  manufacturers  could  not  dis- 
cover any  "  leahy 

Before  purchasing  an  engine  or  any  other  machine,  there  are 
some  very  important  points  to  be  considered  which  involve  its 
commercial  value,  among  which  are,  the  amount  which  it  would 
save  or  earn  over  another  machine  when  in  use,  the  time  it  would 
run  without  repairs,  or  the  addition^  of  any  expenditure  to  its 
original  cost.  For  these  reasons,  the  conditions  that  should  guide 
steam-users  in  the  selection  of  engines  are  steady  motion  under 
varying  circumstances,  economy  of  fuel,  and  cost  of  maintenance. 
In  the  best  types  of  the  steam-engine,  the  principal  expense,  be- 
sides first  cost,  is  fuel ;  but  in  inferior  classes  of  engines,  the  cost 
of  maiotenance,  such  as  lining  up,  and  renewal  of  the  different 
parts,  increases  annually,  until  in  a  few  years  the  cost  in  many  in- 
stances exceeds  that  of  the  fuel.  It  is  to  such  considerations  as 
these  that  steam-users  should  direct  their  attention  when  about  to 
purchase  steam-power,  or  replace  a  worn-out  engine  with  a  new  one. 


THE   engineer's  HANDY-BOOK. 


329 


It  has  not  always  been  the  custom  heretofore  for  those  needing 
steam-power  to  purchase  the  most  economical  engines,  but  rather 
to  buy  for  the  lowest  possible  first  cost,  regardless  of  future  main- 
tenance. Manufacturers  of  inferior  steam-engines  being  aware 
of  this,  agree  to  sell  an  engine  of  a  certain  horse-power  for  a  cer- 
tain price,  perhaps  25  per  cent,  less  than  would  be  asked  for  a 
first-class  machine. 

Many  persons  are  under  the  impression  that  it  requires  more 
fuel  to  carry  steam  at  100  lbs.  per  square  inch  than  at  50  lbs.,  which 
is  evidently  a  mistake,  for  while  it  requires  a  slight  addition  of 
heat  to  raise  it  from  50  to  100  lbs.,  the  expenditure  is  more  than 
compensated  for  by  the  superior  expansion  of  the  steam.  Of 
course,  the  radiation  will  be  greater  at  a  100  lbs.  pressure  per 
square  inch  than  at  50  lbs.;  but  this  would  be  more  than  over- 
balanced by  the  saving  in  the  consumption  of  steam ;  as  steam  at 
70  lbs.  pressure  per  square  inch  will  perform  more  than  seven  times 
as  much  duty  as  steam  at  25  lbs.  pressure. 

Another  fact  not  generally  as  well  known  to  engineers  and 
steam-users  as  it  ought  to  be,  and  which  illustrates  the  benefits  to 
be  derived  from  expansion,  is,  that  if  an  engine  was  taking  steam 
whole  stroke,  or  of  the  piston-stroke,  with  say  60  lbs.  pressure 
per  square  inch,  if  the  pressure  is  raised  to  75  lbs.  per  square  inch 
and  cut  off  at  f  stroke,  the  engine  would  do  the  same  amount  of 
work. 

Location  of  Steam-Engines. 

There  is  no  class  of  machines,  save,  perhaps,  steam-boilers, 
that  are  so  often  injudiciously  located  as  steam-engines ;  they  are 
not  unfrequently  stowed  away  in  out  of  the  way  places,  without 
any  regard  being  paid  to  their  general  appearance.  This  arises 
from  the  fact  that  persons  consulted  on  such  matters  are  allowed 
to  locate  steam-engines  who  are  totally  unfit  to  do  so,  on  account 
of  a  want  of  that  practical  skill  and  experience  that  should  be 
possessed  by  persons  who  undertake  this  duty. 

It  is  a  mistalce  to  locate  an  engine  at  the  extreme  end  of  a 
28* 


330 


THE   ENGINEER'S  HANDY-BOOK. 


building  or  a  long  line  of  shafting,  as,  if  the  engine  were  located 
to  divide  the  work  equally,  the  strain  on  the  section  carrying  the 
driving-pulley  will  be  only  one-half  what  it  would  be  subjected 
to  if  the  motion  were  communicated  from  one  end.  Engines  are 
frequently  so  located  for  the  ostensible  purpose  of  economizing 
space ;  but,  on  examination  of  the  surroundings,  it  will,  in  a  ma- 
jority of  cases,  be  found  that  no  more  space  need  be  occupied  by 
placing  it  in  the  centre,  while  there  would  be  unquestionably  a 
gain  in  the  diminished  friction. 

The  Porter- Allen  High-Speed  Engine. 

The  cut  on  page  331  represents  a  front  view  of  the  Porter- 
Allen  High-Speed  Engine.  As  will  be  observed,  the  bed-plate  is 
of  the  box  form,  the  surface  of  which  is  raised  near  the  centre 
line.  The  main-bearing  being  brought  as  near  as  possible  to  the 
centre  line  of  the  cylinder,  the  breadth  and  depth  being  of 
sufficient  proportion  to  resist  all  strains,  it  presents  no  sharp 
angles  that  would  be  a  source  of  weakness.  In  fact,  the  bed- 
plate was  designed  to  secure  absolute  rigidity  under  high-piston 
velocity,  and  correspondingly  high  steam-pressures,  as  well  as  a 
support  for  the  cylinder,  thus  making  a  self-contained  horizontal 
engine.  The  cylinder  is  overhung  from  the  front  end  of  the  bed- 
plate, without  any  support  excepting  that  which  is  derived  from 
the  butt-joint  which  it  forms  with  the  housing,  which  admits  of 
equal  expansion  on  all  sides,  and  prevents  the  possibility  of  getting 
out  of  line.  The  rigidity  of  these  engines  may  be  judged  from 
the  fact  that  not  the  slightest  vibration  is  experienced  under  the 
highest  piston-velocities  and  steam-pressures ;  nevertheless,  when 
of  necessity  they  have  long  stroke,  there  is  a  temporary  support 
placed  under  the  cylinder. 

The  steam-  and  exhaust-chests  are  located  on  opposite  sides 
of  the  cylinder,  and  cast  in  one  piece  with  it;  and  the  valves  and 
seats  are  so  arranged,  that  the  removal  of  a  small  bonnet  gives 
easy  access  to  them.    At  the  back  of  the  steam- valves,  an  adjust- 


332 


THE   engineer's  HANDY-BOOK. 


able  pressure-plate  is  introduced  ;  this  plate  is  made  of  a  form 
which  is  calculated  to  resist  the  steam-pressure  without  deflection, 
and  which  is  held  against  two  inclined  supports  above  and  below 
the  valve  by  a  bolt  screwed  through  the  bottom  of  the  chest.  If 
this  bolt  is  backed  sufficiently,  the  steam  will  cause  the  pressure- 
plate  to  seize  the  valve.  By  turning  the  bolt  forward,  the  pressure- 
plate  is  raised,  and  also  moved  away  from  the  valve.  The  en- 
gineer can  test  each  valve  for  leakage,  by  unhooking  the  disen- 
gaging hook,  with  which  all  these  engines  are  provided,  and  work 
the  valves  by  hand  under  steam-pressure  by  the  starting-bar,  while 
the  assistant  adjusts  the  bolt  on  the  pressure-plate.  If  there  has 
been  no  wear,  the  slightest  movement  of  the  bolt  will  cause  the 
valves  to  be  seized ;  but  if  there  is  any  wear,  it  can  be  adjusted  in 
a  few  moments. 

The  exhaust-valves  work  under  the  pressure  in  the  cylinder, 
and  have  short  movements,  each  valve  opening  four  passages  for 
the  release  of  the  steam.  The  exhaust-valve  seats  are  formed  on 
the  covers  of  the  chambers  in  which  they  work,  and  on  which, 
also,  the  outlets  are  cast.  They  drain  the  bottom  of  the  cylinder ; 
they  are  very  conveniently  arranged  for  facing,  adjustment,  or  re- 
pairs, and,  by  removing  small  bonnets,  they  may  be  taken  out  and 
replaced  without  any  inconvenience.  The  release  of  the  steam  is 
one  of  the  most  remarkable  features  of  these  engines,  as  the  link 
gives  to  the  valve  an  admirable  movement  in  every  respect.  The 
movement  of  the  exhaust-valves  being  most  rapid  at  the  instant 
of  release,  the  steam  can  be  held'  to  almost  the  end  of  the  stroke, 
in  consequence  of  the  port  opening  to  its  full  width  at  the  instant 
the  crank  reaches  the  centre. 

The  eccentric  is  forged  on  the  shaft,  which  gives  compactness, 
exactness  of  construction,  and  prevents  it  being  shifted  by  acci- 
dent or  design.  The  cylinder-heads  are  designed  to  receive  the 
steam  from  the  boiler,  by  which  arrangement  the  clearance  is  re- 
duced to  a  minimum,  and  the  economy  of  the  engine  increased. 
Great  pains  are  taken  with  the  crank-  and  cross-head  pins,  which 
are  made  of  the  best  steel,  and  hardened.    The  connecting-rod 


THE   engineer's  HANDY-BOOK. 


333 


boxes  are  made  of  gun-inetal  or  bronze.  The  upper  and  lower 
sides  of  the  cross-head  wrist  are  made  flat.  The  crank-pins  are 
of  unusual  diameter  in  proportion  to  their  length,  which  brings 
the  flattened  connecting-rods  close  up  to  the  faces  of  the  accurately 
balanced  disc-cranks.  The  construction  of  the  marine  pillow- 
block  bearings  is  the  result  of  much  study,  and  presents  many 
improvements  over  those  to  be  seen  in  ordinary  engines.  The  fly- 
wheels of  these  engines,  like  the  cranks,  are  turned  and  accurately 
balanced,  which  insures  smooth  motion  in  the  revolving  and  re- 
ciprocating mechanism.  The  regulator  employed  on  these  engines 
is  what  is  known  as  the  Porter  governor,  and  is  peculiarly  adapted 
to  this  class  of  engines ;  and,  in  consequence  of  being  more  powerful 
and  sensitive  than  any  other  governor  in  the  country,  it  has  been 
successfully  applied  to  the  controlling  of  the  valves  of  other  en- 
gines which  no  other  governor  in  the  market  would  regulate. 

The  high-speed  engine  has  not  been  heretofore  appreciated  in 
this  country.  As  has  been  heretofore  stated  in  this  book,  most  in- 
telligent American  engineers  entertain  the  idea  that  there  is 
nothing  to  be  gained  by  running  an  engine  at  such  high  velocity, 
or  employing  extraordinary  high  pressure,  because  an  engine,  to 
run  at  such  an  extraordinary  speed,  needs  to  be  built  with  great 
care,  of  first-class  and  expensive  material,  which  increases  its 
first  cost.  Besides,  the  cost  of  maintenance  of  such  a  machine  is 
a  continual  source  of  annoyance.  It  is  a  well-established  fact  in 
mechanism,  that  haste,  beyond  a  certain  limit,  induces  waste,  and 
that  any  attempt  to  force  any  machine,  steam-engines  and  boilers 
included,  induces  rapid  wear,  deterioration,  and  eventually  the 
destruction  of  the  machine.  The  high-speed  engine  is  one  of  the 
innovations  that  at  difierent  times,  in  the  opinion  of  their  advo- 
cates, were  going  to  revolutionize  the  whole  system  of  steam 
engineering.  But  their  impracticability  soon  became  evident,  and 
they  died  out,  only  to  give  place  to  another  set  of  schemes  that 
have  proved  equally  delusive. 


334  THE   ENGINEER'S  HANDY-BOOK. 

Questions. 

What  are  the  functions  of  the  steam-engine  indicator? 

How  would  you  proceed  to  attach  the  indicator? 

Under  what  three  heads  may  the  particulars  derived  from  an 
indicator  diagram  be  classed  ? 

State  the  conditions  which  are  instrumental  in  determining  the 
conformation  of  a  diagram. 

Explain  the  points  of  difference  between  diagrams  taken  from 
automatic  cut-off  engines  and  those  taken  from  slide-valve  throt- 
tling engines. 

How  would  you  draw  the  theoretical  .expansion  curve  geomet- 
rically? 

How  would  you  trace  a  theoretical  compression  curve? 

From  what  circumstances  does  the  inaccuracy  of  the  theoretical 
curve  arise  ? 

Describe  the  adiabatic  curve. 

How  would  you  locate  the  theoretical  terminal  pressure  cor- 
responding to  the  actual  cut-off? 

How  do  you  account  for  the  difference  in  theoretical  correctness 
as  shown  by  expansion  curves  of  diagrams  taken  from  different 
engines? 

Why  is  the  incorrectness  of  the  expansion  curve  less  with  an 
engine  heavily  loaded  than  with  a  light  load  ? 

If  the  deviation  of  the  expansion  curve  in  diagrams  (other 
things  being  equal)  be  found  to  be  greatest  when  the  water  is 
high  in  the  boilers,  and  the  steam  rapidly  generated,  to  what 
cause  might  it  be  assigned  ? 


THE   ENGINEER\s   HANDY-BOOK.  335 

What  is  the  most  obvious  lesson  to  be  deduced  from  the  facts 
in  our  possession  in  regard  to  the  incorrectness  of  the  curves  of 
diagrams  taken  from  large  engines  ? 

What  should  be  considered  in  indicator  diagrams  as  indications 

of  good  construction  and  performance? 

How  do  you  calculate  the  mean  effective  pressure  ? 

How  would  you  space  the  ordinates  ? 

How  do  you  calculate  the  indicated  horse-power? 

How  do  you  calculate  the  theoretical  consumption  of  water 
from  indicator  diagrams  ? 

How  do  you  make  allowance  for  clearance  and  cushion? 

How  do  you  estimate  the  effect  of  compression? 

What  is  the  object  of  indicator  diagrams  ? 

What  information  do  indicator  diagrams  supply? 

How  do  indicator  diagrams  show  the  steam-pressure  in  the  cyl- 
inder ? 

When  the  line  representing  the  back  pressure  in  the  diagrams 
of  high-pressure  engines  shows  more  than  one  pound  above  atmos- 
phere, or  in  low-pressure  engines  more  than  two  or  three  pounds 
than  the  vacuum-gauge  shows  in  the  condenser,  what  does  the  dia- 
gram indicate? 

How  does  the  diagram  show  whether  the  valves  are  properly 
set  or  not? 

How  does  the  diagram  show  whether  the  piston  and  valves  are 

leaking  or  not  ? 

How  does  the  diagram  show  whether  the  steam  is  throttled  or 
not? 


i 

336  THE  engineer\s  handy-book. 

How  does  the  diagram  show  the  effect  of  small  steam-ports 
and  steam  connections  ? 

How  does  the  diagram  show  the  effect  of  exhaust  lead? 

How  does  the  diagram  show  that  the  indicator  is  out  of  order? 

How  does  a  diagram  show  the  point  of  cut-off? 

How  does  a  diagram  show  the  state  of  the  vacuum  in  the  con- 
denser,  and  whether  too  much  injection- water  is  used  or  not  ? 

Sketch  a  diagram,  and  explain  it. 

Show  the  points  of  excellence  in  a  perfect  diagram. 

Show  the  steam,  atmospheric,  and  vacuum  lines  and  the  ex- 
pansion and  exhaust  curves. 

Define  the  adiabatic  curve,  and  explain  how  it  is  obtained. 

Define  the  asymptote  lines. 

Define  the  term  compression. 

Define  the  term  cushion. 

Define  the  term  clearance. 

Define  the  terms  flexure  and  contrary  flexure,  and  demonstrate 
them  on  the  diagram. 

Define  the  term  hyperbola,  and  illustrate  it. 

Give  the  meaning  of  the  term  isothermal.  i 
Point  out  the  ordinates  on  the  diagram. 
Define  the  term  parallelism. 
-   What  is  meant  by  the  initial-pressure?  ? 


THE   engineer's   HANDY-BOOK.  337 

What  is  meant  by  the  term  mean  effective  pressure? 

What  Is  meant  by  the  term  terminal-pressure? 

What  is  meant  by  the  term  scale  in  its  application  to  the  diagram  ? 

Explain  the  functions  of  the  spring  in  its  relations  to  the  indicator. 

Explain  the  meaning  of  I.  H.  P.,  N.  H.  P.,  M.  E.  P.,  and  H.  P. 

Explain  the  meaning  of  the  term  string. 

Define  the  term  undulating. 

What  are  the  use  and  functions  of  the  dynamometer? 

What  is  the  meaning  of  the  letters  B  and  T  which  are  fre- 
quently seen  on  diagrams  ? 

Define  the  term  zero  when  applied  to  indicator  diagrams. 

Give  the  formula  for  finding  the  horse-power  of  an  engine  from 
indicator  diagrams. 

What  are  the  functions  of  the  planimeter? 

Explain  the  most  correct  method  of  using  the  planimeter. 

What  is  the  exponent  of  the  work  performed  by  a  steam-engine? 
For  the  meaning  of  the  4erm  mean  effective  pressure,  see  page  259. 

What  is  the  best  criterion  of  the  most  economical  results  which 
a  steam-engine  is  capable  of  producing? 

Before  purchasing  a  steam-engine  or  other  machinery,  what 

considerations  ought  to  be  taken  into  account  ? 

Is  there  any  difference  in  the  consumption  of  fuel  required  to 
carry  steam  at  100  lbs.  pressure  instead  of  50  lbs.  per  square  inch  ? 

How  should  engines  in  factories  be  located? 
29  W 


338 


THE  ENGINEEE's  HANDY-BOOK. 


PART  FIFTH. 


Condensers. 

The  condenser  is  one  of  the  most  necessary  and  important  ad 

^^"^  juncts  of  the  low-pressure  engine,  as  in 

the  perfection  of  the  vacuum  produced  in 
it  by  the  condensation  of  the  steam  lies 
the  economy  of  that  class  of  machines. 
All  the  other  parts  of  the  engine  may  be 
modified,  and  many  of  them,  in  some 
cases,  dispensed  with,  as  in  the  trunk 
and  oscillating  engines.  Even  the  air- 
pump,  as  has  been  shown  in  a  former 
article,  is  not  an  absolute  necessity;  but, 
whatever  changes  a  condensing  engine 
may  undergo,  the  presence  of  the  con- 
denser is  an  imperative  necessity. 

The  two  kinds  of  condensers  in  gen- 
eral use  are  known  as  the  jet  and  sur- 
face. The  surface  condenser  consists 
of  an  iron  box,  in  which  brass  or  copper 
tubes  are  inserted  in  tube  sheets,  simi- 
lar to  those  of  a  tubular  steam-boiler, 
through  which  the  water  is  forced  by 
the  circulating  pump,  for  the  purpose 
of  condensing  the  steam.  In  some  cases 
condensation  is  effected  by  bringing  the 
exhaust  steam  in  contact  with  the  out- 
side of  the  tubes,  the  circulating  water 
being  on  the  inside ;  while  in  others  the 


OpoOOOOoOGn 


End  View  of  a  Surface 
Condenser  with  the 
Bonnet  removed.  _ 

Steam  is  exhausted  into  the  tubes,  and  the  circulating  water 

distributed  on  the  outside  of  them.    There  is  no  especial  ad 


THE   ENGINEER\s  HANDY-BOOK. 


339 


vautage  in  the  former  over  the  latter,  nor  vice  versa,  the  ar- 
rangement being  only  a  matter  of  taste.  In  the  proportioning  of 
either  surface  or  jet  condensers  there  appears  to  be  great  latitudtr 
in  practice,  but  in  the  surface  condenser  a  certain  amount  of  coolinf^ 
surface  must  be  provided  ;  more  than  the  required  quantity  is  a  waste 
of  material,  and  incurs  unnecessary  weight  and  first  cost,  besides  the 
extra  time  required  to  remove  the  air  before  starting.  The  objec- 
tion to  a  small  condenser  is,  that  in  case  the  air-pump  should  fail  to 
operate  properly,  the  condenser  would  soon  become  choked  with 
water ;  the  best  guide  in  such  cases  is  practical  experience. 

In  the  surface  condenser,  the  cold  water  is  lifted  by  a  circulat- 
ing pump  through  a  pipe  in  the  ship^s  side  or  bottom  and  forced 
through  the  tubes,  and  thence  overboard.  The  number  of  times 
the  w^ater  circulates,  depends  on  the  design  and  arrangement  of 
the  condenser.  In  some  condensers  it  circulates  once,  in  others 
twice,  and  in  others  three  or  even  four  times.  In  the  cut  on  page 
838  the  steam  enters  at  A,  and  the  injection- water  at  J5,  which 
returns  through  section  C,  re- returns  through  section  D,  and  is 
forced  overboard  through  E.  F  represents  the  hot  well  contain- 
ing the  water  of  condensation,  which  is  returned  to  the  boilers  by 
means  of  the  boiler  feed-pumps. 

The  capacity  of  the  circulating  pumps  of  the  best  class  of  sur- 
face-condensing, compound  engines  is  about  1  to  22,  or  1  cubic 
foot  of  circulating  pump  capacity  to  22  feet  in  the  low-pressure 
cylinder,  and  in  the  proportion  of  about  1  cubic  foot  of  circulating 
pump  capacity  to  688  feet  of  cooling  surface  in  the  tubes  of  the 
condenser.  The  proportion  of  cooling  surface  in  the  best  class  of 
surface  condensers  is  about  28  square  feet  of  cooling  surfiice  to  1 
cubic  foot  in  the  low-pressure  cylinder,  or  6j  square  feet  to  the 
indicated  horse-power. 

The  advantages  of  surface  condensers  are,  that  they  furnish 
fresh  water  to  the  boilers,  (since  the  sea  injection-water  does  not 
mingle  w^ith  the  water  of  condensation,  thus  obviating  the  loss  in- 
duced by  scale  in  the  boiler,)  that  steam  of  any  pressure  can  be 
condensed,  and  that  the  vacuum  is  more  perfect  than  in  the  jet 


340 


THE   ENGINEER'S  HANDY-BOOK. 


condensers.  Their  disadvantages  are,  extra  weight  and  first  cost,  and 
that  the  tubes  are  liable  to  become  leaky,  and  impair  the  vacuum. 
In  case  the  tubes  should  become  so  leaky  as  to  be  beyond  remedy, 
the  surface  condenser  may  be  converted  into  a  jet  condenser  by 
admitting  the  exhaust  steam  and  injection- water  above  the  tubes  ; 
but  the  jet  condenser  cannot  be  changed  into  a  surface  condenser 
under  any  circumstances. 

The  tubes  of  surface  condensers  are  made  of  brass  or  copper, 
generally  about  |  of  an  inch  in  diameter.  They  were  formerly 
riveted  into  the  heads  or  tube  sheets,  but  in  consequence  of  the 
lightness  of  the  material  of  which  they  are  composed,  and  of  its 
great  limit  of  expansion,  they  soon  became  loose  and  leaky,  as  a 
result  of  which  riveting  was  abandoned.  They  are  now  generally 
made  tight  by  means  of  some  fibrous  material,  such  as  cotton  or 
India-rubber,  but  more  recently  by  brushings  of  kiln-dried  or  con- 
densed wood. 

The  jet  condenser  consists  of  an  iron  pot  or  shell,  into  which 
the  steam  is  exhausted.  The  water  rises  through  a  pipe  in  the 
ship's  side,  by  the  pressure  of  the  atmosphere,  and  is  distributed 
by  a  rose,  an  arrangement  similar  to  the  nozzle  of  an  ordinary 
garden  watering-pot,  which,  as  it  frequently  became  choked  by 
substances  carried  in  by  the  injection- water,  was  abandoned.  The 
distribution  of  the  water  is  now  effected  by  allowing  it  to  strike  a 
cone  in  the  cover  of  the  condenser. 

The  capacity  of  jet  condensers  may  be  from  j\  to  -^q  the  ca- 
pacity of  the  steam-cylinder,  or  it  may  be  of  the  same  capacity  as 
the  air-pump.  The  advantages  of  a  jet  condenser  are,  that  it  is 
light,  simple,  and  inexpensive;  and  its  disadvantages,  that  the 
saline  matter  contained  in  the  injection-water  is  carried  into  the 
boilers,  which  lessens  the  economy  of  fuel,  and  that  steam  of  a 
very  high  pressure  cannot  be  successfully  condensed  in  it.  Should 
the  condenser  become  so  impaired,  as  to  be  incapable  of  creating  a 
vacuum,  the  connection  between  the  condenser  and  the  engine 
may  be  separated,  and  the  engine  allowed  to  exhaust  into  the  at^ 
mosphere,  when  it  becomes  a  non-condensing  engine. 


THE   engineer's   HANDY-BOOK.  341 

A  snifting-valve  is  fixed  on  the  condenser  to  allow  the  air  and 
water  to  escape  when  the  condenser  is  blown  through.  The  vac- 
uum in  the  condenser  keeps  it  closed,  and,  in  the  event  of  a  great 
head  of  water,  or  pressure  in  the  condenser,  tlie  valve  will  ease 
up  and  allow  it  to  escape. 

TABLE 


SHOWING  THE  FORCE  WITH  WHICH  THE  UNCONDENSED  STEAM  ARISING 
FROM  THE  WATER  IN  THE  CONDENSER  RESISTS  THE  ASCENT  OR  DESCENT 
OF  THE  PISTON,  ACCORDING  TO  ITS  TEMPERATURE. 


t-.ti 

.S  o  b 

9^  • 

•So  b 

1-  JS 

V  o 

CL  a 

Tempera 
Fahrenl 

Force 

Inches 

MerciiJ 

Pounds 
Square  I 

Tempera 
Fahrenli 

Force 

Inches 

Mercui 

Founds 
Square  I 

32 

0-200 

0-100 

130 

4-36 

2-17 

40 

0-250 

0-128 

135 

507 

2-52 

50 

0-360 

0-181 

140 

5-77 

2-88 

55 

0-416 

0-215 

145 

6-60 

3-28 

60 

0-516 

0-260 

150 

7-53 

3-74 

65 

0-630 

0-311 

155 

8-50 

4-22 

70 

0-726 

0-361 

160 

9-60 

4-76 

75 

0-860 

0-428 

165 

10-80 

5-37 

80 

1-01 

0-505 

170 

12-05 

6-04 

85 

1-17 

0-585 

175 

13-55 

6-75 

90 

1-36 

0-680 

180 

15-16 

7-58 

95 

1-58 

0-805 

185 

16-90 

8-47 

100 

1-86 

0-900 

190 

19-00 

9-50 

105 

2-10 

1-07 

195 

21-10 

10-58 

110 

2-53 

1-26 

200 

23-60 

11-81 

115 

2-82 

1-43 

205 

25-90 

13-01 

120 

3-30 

1-50 

210 

28-88 

14-43 

125 

3-83 

1-902 

212 

30- 

15- 

The  temperature  of  the  \vater  in  the  hot  wells  of  surface-con- 
densing engines  is  generally  about  100°  to  110°  Fah.    A  higher 
temperature  would  affect  the  vacuum  and  injure  the  air-pump 
29* 


342 


THE   engineer's  HANDY-BOOK. 


valves,  while  a  lower  temperature  would  cool  the  cylinder,  and 
cause  a  waste  of  fuel  by  the  condensation  of  the  steam.  A  very 
low  temperature  causes  increased  consumption  of  fuel,  while  a  very 
high  one  causes  a  loss  of  power,  owing  to  the  back  pressure  in- 
duced by  the  uncondensed  vapor  in  the  condenser,  which  will  be 
shown  by  the  vacuum-gauge. 

In  the  jet  condenser,  when  the  bilge-injection  is  opened,  the  air- 
pump  draws  off  the  air  from  the  pipe,  when  the  air  in  the  ship, 
pressing  on  the  surface  of  the  bilge-water,  forces  it  up  the  pipe 
into  the  condenser.  In  the  surface  condenser  the  circulating 
pump  creates  the  vacuum,  and  the  air  presses  the  water  up. 

In  a  jet  condenser,  if  the  injection-water  is  not  shut  off  when 
the  engines  are  stopped,  the  condenser  will  be  filled  with  water, 
and,  if  not  cleared  before  the  engine  is  started,  may  cause  serious 
damage  to  the  cylinder  or  condenser. 

Relative  Quantity  of  Injection- Water  Required  to  Con- 
dense a  Certain  Tolume  of  Steam. 

The  weight  op  quantity  of  injection-  or  condensing-water  re- 
quired for  a  given  weight  or  volume  of  steam  depends  upon 
several  conditions :  1.  The  pressure  at  which  the  steam  is  ex- 
hausted. 2.  The  absolute  pressure  existing  in  the  condenser  after 
the  vacuum  has  been  formed.  3.  The  temperature  at  which  the 
injection- water  enters  the  condenser.  While  the  first  and  second 
conditions  vary  but  slightly  with  uniform  load  and  steam  pressure, 
the  third  will  vary  with  the  season,  and  even  with  the  weather; 
consequently,  more  condensing-water  is  required  in  summer  than 
in  winter.  But  the  average  amount  may  be  illustrated  as 
follows: 

Example. —  Suppose  the  pressure  in  the  cylinder  at  release  or 
exhaust  be  5  lbs.  above  atmosphere,  and  the  absolute  pressure  in 
the  condenser,  after  vacuum  is  formed,  be  2  lbs.,  corresponding  to 
a  vacuum  of  26  inches  of  mercury.  Each  pound  of  steam  ex. 
hausted  at  5  lbs.  above  atmosphere  contains  1183  thermal  units, 


THE   ENGINEER\s  HANDY-BOOK. 


343 


and  the  thermal  units  per  pound  of  condensation  at  2  lbs.  abso- 
lute pressure  in  the  condenser  are  126.  Hence  the  thermal  units 
to  be  absorbed  by  the  condensing-water  are  1183  — 126  =  1057. 
Suppose  the  temperature  of  the  injection-water  be  80°  Fah.,  then 
each  pound  of  condensing-water  takes  up  126  —  80  =  46  thermal 
units ;  and  pounds  of  condensing-water  per  pound  of  steam  con- 
densed become  =  23  nearly.  Suppose,  again,  that  the  tem- 
perature of  the  injection-water  be  40*^  Fah.,  then  each  pound  of 
condensing-water  takes  up  126  —  40  =  86  thermal  units,  and 
pounds  of  condensing-water  per  lb.  of  steam   condensed  are 

^^^^  =  12*3  lbs.,  from  which  it  will  be  seen  that  the  average  pro- 
portion of  condensing-water  to  the  wetter  of  condensation  is  about 
as  18  to  1. 

Rule  for  finding  the  cooling  surface  in  the  tubes  of  surface  con- 
densers. 

Multiply  the  circumference  of  one  tube  in  inches  by  its  length 
in  inches;  then  multiply  that  product  by  the  whole  number  of 
tubes,  and  divide  by  144.  The  quotient  will  be  the  number  of 
square  feet  of  cooling  surface  in  the.  tubes. 

The  tubes  of  surface  condensers  frequently  become  foul  on 
the  inside,  owing  to  the  grease  used  to  lubricate  the  cylinder  being 
carried  over  with  the  exhaust  steam,  and  they  become  foul  on  the 
outside  by  the  saline  matter  in  the  injection- water  adhering  to 
them.  There  are  various  ways  of  cleansing  them,  one  of  which 
is  to  admit  steam  of  a  high  pressure  from  the  boiler  to  the  con- 
denser. Another  is  to  fill  the  condenser  with  a  strong  solution 
of  soda  of  potash,  but  in  both  cases  care  must  be  taken  not  to 
destroy  the  packing  round  the  tubes,  of  whatever  material  it  may 
be  composed.  If  the  tubes  are  packed  with  wood,  and  allowed  to 
become  too  hot  by  the  action  of  the  steam,  they  will  become 
charred  and  drop  out ;  if  packed  with  India-rubber,  they  will  be 
destroyed  by  too  high  a  temperature ;  if  the  solution  of  potash 
used  to  clean  them  is  too  strong,  they  are  liable  to  be  ruined. 


344 


THE  ENGINEER'S 


HANBY- 


BOOK. 


The  Injector  Condenser. 


A  shows  the  steam-pipe ;  the  stop-valve ;  C,  the  exhaust-pipe ;  E,  the 
annular  head  into  which  the  condensing-water  is  thrown  through  the 
pipe,  and  by  the  arrangement  of  which  the  water  is  formed  into  a 
sheet;  jPi^ shows  the  two  inverted  nozzles  through  which  the  condensing- 
water  escapes  into  the  hot  well,  H, 


THE   engineer's  HANDY-BOOK. 


345 


The  Injector  Condenser. 

The  cut  on  the  opposite  page  represents  the  injector  condenser,  so 
called  because  its  action  is  similar  to  that  of  the  Giffard  boiler  feed- 
injector.  It  consists  of  two  conoidal  nozzles,  joined  by  a  straight 
neck,  and  swelled  at  the  upper  end  for  the  junction  of  the  water- 
^j.zie.  Within  is  the  exhaust-steam  nozzle,  which  forms  withm 
the  condenser  a  narrow,  annular  space  for  the  entrance  of  the  con- 
densing-water.  The  sides  of  the  condenser  (which  are  parab- 
oloidal  curves)  are  smoothly  finished,  as  is  the  contracted  neck 
below,  to  diminish  the  resistance  of  the  water.  When  used  m 
connection  with  a  condensing  engine,  the  air-pump  may  be  dis^ 
pensed  with,  as  steam  of  atmospheric  pressure  will  flow  into  a 
vacuum  at  the  rate  of  1600  feet  per  second. 

When  the  exhaust  steam  from  the  engine  meets  the  thin  fihn 
of  water  which  enters  by  the  annular  space,  it  is  instantly  con- 
densed. As  the  water  passes  down,  the  contracting  outline  of  the 
condenser  gradually  brings  it  to  a  solid  jet  in  the  neck  below, 
through  which  it  rushes  with  a  velocity  due  to  its  pressure.  The 
air  which  has  entered  the  condenser  with  the  water,  or  through 
leaky  joints  or  stuffing-boxes,  together  with' the  uncondensed 
vapor,  is  thus  drawn  down  into  a  contracting,  hollow  cone  of 
water,  until  finally  expelled  through  the  neck.  This  latter  being 
straight  for  a  distance,  is  virtually  the  air-pump,  having  a  solid 
piston  of  water  moving  at  a  high  speed ;  thus  is  the  steam  con- 
densed, and  the  vacuum  formed  by  a  single  process,  and  with 
greater  certainty  *than  in  any  other  way.  The  air  and  vapor 
having  passed  the  contracted  neck,  enter  the  tapering  nozzle 
below,  and  expanding  therein  are  prevented  from  returning  to 
the  condenser  above. 

The  method  of  operation  of  the  injector  condenser  when  the  en- 
gine is  started  is  as  follows :  the  exhaust  steam  expels  the  air  from 
the  exhaust-pipe  and  condenser  ;  then  a  jet  of  cold  water  from  a 
pump  or  tank  creates  a  vacuum,  which  may  be  maintained  by  a 
head  of  water  of  10  feet  fall.    The  discharge-water  passes  off*  at 


346 


THE   engineer's  HANDY-BOOK. 


a  temperature  of  110°  to  112°,  when  the  vacuum  is  equal  to  26 
inches  of  mercury. 

The  advantages  of  the  injector  condenser  are,  that  it  is  cheap, 
light,  simple,  and  durable ;  that  the  injection-water  is  self-regu- 
lating ;  that  there  is  no  possibility  of  the  water  being  carried  over 
into  the  cylinder ;  that,  simply  by  the  removal  of  a  bonnet,  the 
exhaust  steam  may  be  allowed  to  escape  into  the  atmosphere,  thus 
converting  the  engine  from  low  to  high  pressure ;  that  the  con- 
denser requires  no  foundation  or  any  other  attachment  save  an  or- 
dinary pump  to  raise  the  water  when  there  is  not  sufficient  fall ; 
and  that  the  condenser  can  be  attached  to  any  engine  in  any  lo- 
cality where  the  necessary  supply  of  water  can  be  obtained,  which 
ranges  from  22  to  25  times  as  much  as  that  from  which  the  steam 
would  be  generated.  It  is  claimed  that  a  saving  of  over  20  per 
cent,  may  be  made  where  these  condensers  are  used,  while  the  first 
cost  is  trifling. 

Independent  Condenser  and  Air-Pump. 

The  annexed  cut  represents  a  very  ingenious  and  convenient 
combined  condenser  and  air-pump,  designed  by  Edwin  Reynolds, 
and  manufactured  by  E.  P.  Allis  &  Co.,  Milwaukee,  Wisconsin, 
to  be  used  in  connection  with  the  Reynolds  Corliss  engine,  and 
which  can,  in  case  of  accident  to  the  engine  which  drives  the 
machinery,  be  used  as  an  independent  or  auxiliary  engine,  which 
may  be  used  while  making  repairs.  A  foot-valve  is  entirely  dis- 
pensed with,  and  only  bucket-  and  delivery-valves  used.  They 
are  fitted  up  either  with  or  without  a  steam-cylinder,  and  when 
the  latter  is  dispensed  with  the  air-pump  is  driven  by  a  belt 
from  the  engine  to  the  wheel,  T ;  but  when  driven  by  the  steam- 
cylinder  a  regulator  is  employed,  which  is  not  shown  in  the  cut. 
The  barrel.  A,  which  is  bored  out  on  a  line  with  the  steam-cylinder, 
a,  forms  a  cross-head  guide,  to  which  the  steam-piston  is  attached. 
Four  rods  form  a  connection  with  the  cross-head  of  the  air-pump 
below  the  crank-shaft. 

The  head,  B,  shows  the  bonnet  or  cover  of  the  valve-chamber, 


THE   engineer's  HANDY-BOOK. 


347 


Independent  Condenser  and  Air-Pump. 

Designed  for  the  Reynolds  Corliss  Engine,  and  Manufactured  bv  E.  P 
AUis  &  Co.,  Milwaukee,  Wis.    See  description  on  pages  346  and  348. 


348 


THE   engineer's  HANDY-BOOK. 


and  the  flange,  (7,  the  steam-pipe  connection.  D  represents  the 
bracket  containing  the  valve-stem  stuffing-box,  the  outer  end  of 
which  forms  a  bearing  for  an  oscillating  valve,  to  the  stem  of 
which  the  crank,  E,  is  keyed,  which  operates  the  steam-valve. 
The  swell,  constitutes  the  steam-ports  from  the  valve-chamber 
to  the  end  of  the  steam-cylinder.  G  shows  an  opening  provided 
for  getting  at  the  stuffing-box  of  the  piston-rod  and  oiling  the 
cylindrical  cross-head.  The  eccentric,  jET,  gives  motion  to  the 
steam-valve  through  the  rod,  i?,  and  crank,  A  The  crank  /,  which  is 
slotted  for  the  purpose  of  adjusting  the  length  of  the  stroke,  drives 
the  force-pump,  J,  which  may  be  used  either  as  a  •lift  and  force, 
circulating,  or  boiler  feed-pump,  k  represents  the  delivery-  and  K 
the  suction-pipe.  The  pipe,  M,  is  the  injection-pipe ;  iV,  the  suction 
for  the  force-pump,  which  takes  its  water  from  the  pocket,  S.  The 
valve,  L,  is  used  to  regulate  the  quantity  of  water  admitted  to  the 
force-pump.  The  pipe,  0,  is  the  overflow  from  the  air-pump,  which 
is  in  the  centre  of  the  condenser.  The  plate,  F,  covers  a  man-hole, 
through  which  access  is  had  to  the  valves  and  piston  of  the  air- 
pump. 

The  Yacuum. 

If  the  cylinder  of  a  steam-engine  be  filled  with  vapor,  it  cannot 
be  said  to  be  void  of  matter ;  but  if  the  vapor  is  condensed,  and 
the  water  from  which  it  was  vaporized  drawn  off*,  there  would  be 
created  in  the  cylinder  what  is  termed  a  "  vacuum,"  or  void  space. 
The  absolute  pressure  of  steam  is  measured  from  zero,  or  perfect 
vacuum,  and  consists  of  the  pressure  indicated  by  the  steam-gauge 
(which  is  known  as  pressure  above  atmosphere),  added  to  the 
pressure  of  the  atmosphere,  as  shown  by  the  barometer.  The 
latter  is,  for  all  practical  purposes,  a  constant  quantity  for  any 
given  locality,*  and  may  be  roughly  taken  at  14*5  lbs.,  cor- 
responding to  29*50  inches  of  mercury.  Vacuum-gauges  are 
usually  graduated  to  agree  with  the  scale  of  the  barometer,  and 
the  vacuum  is  usually  stated  in  inches  of  mercury.  To  the  steam- 


*  See  Table  on  page  498. 


THE   ENGINEER'S  HANDY-BOOK. 


349 


pressure,  as  indicated  by  the  gauge,  add  14*5  lbs.  for  total  press- 
ure. Thus,  if  the  pressure  by  gauge  is  60  lbs.,  the  total  pressure 
is  74*5  lbs.  Consequently,  the  total  pressure  on  the  steam  side,  at 
any  point  in  the  stroke  of  the  piston,  is  the  pressure  above  the 
atmosphere  plus  14*5  lbs.,  and  the  total  pressure  for  the  whole 
stroke  is  the  mean-pressure  above  the  atmosphere  plus  14*5  lbs. 
Thus,  if  the  mean-pressure  for  whole  stroke  is  30  lbs.,  the  total 
mean-pressure  is  44*5  lbs. ;  and  this  44*5  lbs.,  whether  the  engine 
is  condensing  or  non-condensing,  is  the  variable  factor  in  estima- 
ting the  load  on  the  engine.  Now,  if  the  engine  be  non-conden- 
sing, the  14*5  lbs.  (pressure  of  the  atmosphere)  on  the  steam  side 
of  the  piston  is  balanced  by  an  equal  atmospheric  pressure  on  the 
exhaust  side,  and  its  effect  is  neutralized ;  but  if  the  engine  be 
condensing,  a  large  proportion  of  the  pressure  of  the  atmosphere 
on  the  exhaust  side  of  the  piston  is  removed,  and  an  equivalent 
portion  of  the  pressure  of  the  atmosphere  on  the  steam  side  of  the 
piston  made  to  do  useful  work.  With  well-proportioned  conden- 
sing apparatus,  the  pressure  of  the  atmosphere  on  the  exhaust  side 
of  the  piston  can  be  reduced  nearly  90  per  cent. 

TABLE 


SHOWING  VACUUM  IN  INCHES  OF  MERCURY  AND  POUNDS  PRESSURE  PER 
SQUARE  INCH. 


Mercury. 

POUNDS. 

Mercury. 

Pounds. 

2-037 

1 

16-300 

8 

4-074 

2 

18-337 

9 

6-111 

3 

20-374 

10 

8-148 

4 

22-411 

11 

10-189 

5 

24-448 

12 

12-226 

6 

26-485 

13 

14-263 

7 

28-552 

14 

L 

The  lower  the  temperature  of  the  water  leaving  the  condenser, 
the  better  the  vacuum,  and  the  more  conducive  to  power,  always 
30 


350 


THE    ENGINEER'S  HANDY-BOOK. 


supposing  there  be  no  air-leaks.  Watt  found  a  temperature  of 
100°  in  the  water  leaving  the  condenser  more  beneficial  than  70^ 
or  80°,  supposing  there  be  an  abundant  supply  of  cold  water.  It 
may  be  explained  in  this  way.  A  better  vacuum  due  to  a  tem- 
perature of  70°  or  80°  requires  so  much  cold  water  in  the  con- 
denser, (which  must  afterwards  be  pumped  out  against  the  press- 
ure of  the  atmosphere,)  that  the  gain  in  the  vacuum  does  not 
equal  the  loss  of  power  caused  by  the  additional  load  on  the  pump. 
There  is,  therefore,  a  clear  loss  by  the  reduction  of  the  temper- 
ature below  100°,  if  such  reduction  be  caused  by  the  admission 
of  an  additional  quantity  of  water. 

The  vacuum  is  maintained  in  the  condenser  by  the  action  of  the 
air-pump.  A  perfect  vacuum  cannot  exist,  and  in  the  condenser 
of  an  engine  there  is  always  more  or  less  pressure  from  imperfect 
condensation,  and  air  passing  in  with  the  condensing-water. 

The  vacuum  is  measured  by  inches  in  the  height  of  a  column 
of  mercury,  2  inches  of  mercury  equalling  one  pound  pressure  per 
square  inch ;  thus,  20  inches  of  mercury  means  10  lbs.  pressure 
per  square  inch.  If  the  steam-gauge  shows  10  lbs.  pressure,  and 
the  vacuum-gauge  registers  20  inches,  there  is  a  vacuum  equal  to 
10  lbs.  per  square  inch  in  the  condenser. 

The  vacuum  is  maintained  in  the  condenser  by  the  exhaust 
steam  being  constantly  condensed,  by  either  mixing  with  the  cold 
injection- water  or  by  being  brought  in  contact  with  the  cooling 
surface  of  the  tubes  in  the  surface  condenser. 

A  vacuum  is  produced  in  a  condenser  by  the  steam  (when  it  first 
enters)  driving  out  the  air ;  and,  when  condensed  into  water,  it  oc- 
cupies 1669  times  less  space  than  it  did  before  being  condensed, 
as  1700  cubic  feet  of  steam  produce  one  cubic  foot  of  water. 

To  produce  a  vacuum  in  a  jet  condenser,  open  the  blow-through 
valve,  when  the  steam,  in  its  passage  through,  will  blow  out  all 
air  and  water  in  the  condenser;  and  as  soon  as  the  steam  issues 
from  the  snifting-valve  the  blow-through  valve  may  be  shut,  and 
the  injection-cocks  opened,  wh6n  the  cold  water  mixing  with  the 
steam  forms  a  vacuum.    When  the  gauge  shows  a  sufficient  vac- 


THE   ENGINEEr\s  HANDY-BOOK. 


351 


uum,  shut  the  injection-cocks,  in  order  to  prevent  the  condenser 
from  being  flooded. 

To  produce  a  vacuum  in  a  surface  condenser,  open  the  injection- 
valve  shortly  before  starting  the  engine,  so  that  the  circulating- 
water  may  enter  the  condenser  tubes,  and  cool  them.  Then,  when 
the  engine  is  started,  the  exhaust  steam  comes  in  contact  with  the 
cooling  surface  of  the  tubes,  and  is  condensed  when  a  vacuum  is 
formed. 

If  the  steam-gauge  shows  60  lbs.  pressure,  and  the  vacuum- 
gauge  26  inches,  it  means  that  there  are  60  lbs.  of  steam  pressing 
on  one  side  of  the  piston,  and  13  lbs.  of  resistance  removed  from 
the  other  side. 

The  state  of  the  vacuum  is  shown  by  the  vacuum-gauge  attached 
to  the  condenser ;  and,  if  it  be  imperfect,  the  cause  must  be  ascer- 
tained and  the  fault  corrected.  If  the  water  in  the  hot  well  be 
above  the  ordinary  temperature,  more  injection- water  must  be  ad- 
mitted ;  and,  if  the  vacuum  continues  imperfect,  the  cause  may  be 
due  to  an  air-leak,  the  location  of  which  the  engineer  must 
endeavor  to  discover.  Very  often  the  fault  will  be  found  in  the 
valve-  or  cylinder-cover,  which  must  then  be  screwed  down  more 
firmly ;  or  in  the  joint  of  the  eduction-pipe,  the  gland  of  which 
will  require  to  be  tightened.  The  door  of  the  condenser  should 
also  be  examined.  The  joints  of  the  condenser  may  be  tested  by 
holding  a  candle  to  them,  the  flame  of  which  will  be  drawn  in  if 
the  joints  are  leaky. 

A  vacuum  is  not  power,  as  all  power  in  the  steam-engine  is  de- 
rived from  the  pressure  of  the  steam  on  the  piston ;  if  there  is  no 
resistance  on  one  side  of  the  piston,  the  entire  pressure  on  the 
other  side  is  available.  Whenever  there  is  resistance  on  one  side 
of  the  piston,  it  must  be  deducted  from  the  pressure  on  the  other 
side.  There  is  hardly  such  a  thing  as  a  perfect  vacuum.  The 
philosopher  Torricelli  asserted  correctly  that  nature  abhors  a 
vacuum  ;  consequently,  if  a  perfect  vacuum  can  be  attained,  it  can- 
not be  maintained  long,  as  the  wear  of  the  machinery,  the  packing 
around  the  air-pump  rod,  and  other  causes,  contribute  to  impair  it. 


THE   ENQINEER\s  HANDY-BOOK. 


353 


Air-Pumps. 

All  condensing  engines  have  of  necessity  to  be  provided  with 


an  air-pump,  for  the  purpose  of  extracting 
water,  and  the  water  of  condensation  from 
the  condenser,  in.  order  to  maintain  a  vac- 
There  does  not  appear  to  be  any 


injection- 


uum. 


uniform,  recognized  rule,  among  marine 
engineers  or  manufacturers  of  surface-con- 
densing compound  engines,  for  proportion- 
ing the  air-pumps  to  the  steam-cylinder,  as, 
while  some  builders  make  the  capacity  of 
their  air-pumps  one-eighth  of  that  of  the 
low-pressure  cylinder,  others  make  it  one- 
tenth,  and  others  one-eleventh  ;  the  average 
of  the  number  examined  being  about  one- 
ninth. 

The  air-pumps  of  the  steamships  Penn- 
sylvania, Ohio,  Indiana,  and  Illinois,  of  the 
American  Line,  are  one-eleventh  the  capac- 
ity of  the  low-pressure  cylinder.  And,  as 
these  engines  have  the  reputation  of  being 
very  economical,  it  should  be  presumed*  g^^^i^^  ^^^^  ^j^^^^i^^ 
that  their  proportions  are  good  ;  neverthe-  Pump, 
less,  they  are  evidently  too  large,  as  one-fifteenth  would  be  nearer 
to  a  correct  proportion.  The  tendency  among  marine  engineers  is 
to  overdo  the  thing  in  the  case  of  air-pumps,  perhaps  under  the  im- 
pression that  a  large  air-pump  creates  a  better  vacuum,  and,  as  a 
result,  air-pumps  of  enormous  diameter  and  long  stroke  are  at- 
tached to  marine  engines ;  whereas,  the  air-pump  has  very  little  to 
do  with  the  vacuum,  its  functions  being  simply  to  clear  the  con- 
denser of  water  and  air.  Any  proportion  that  will  accomplish  this 
will  fulfil  all  the  necessary  requirements.  An  air-pump  too  large 
for  the  purpose  for  which  it  is  intended,  can  have  no  other  eflTect 
than  to  absorb  much  of  the  power  which  might  be  utilized  in  in- 
30*  X 


354 


THE   ENGINEER'S  HANDY-BOOK. 


creasing  the  speed  of  the  engine  and  economizing  the  fuel.  The  air- 
pump  piston,  being  resisted  by  the  pressure  of  the  atmosphere,  ab- 
sorbs from  four  to  five  per  cent,  of  the  power  of  ordinary  simple  con- 
densing engines,  and  from  two  to  three  per  cent,  in  the  better  class 
of  compound  marine  engines  ;  the  power  required  to  work  it  being 
greatest  when  the  vacuum  is  most  perfect,  and  least  when  the 
vacuum  is  impaired.  A  good  deal  also  depends  on  the  mechanical 
arrangement  employed  to  work  it,  as  well  as  on  the  condition  of 
its  packings,  bearings,  proportions,  etc. 

The  capacity  of  the  air-pumps  of  condensing  engines  using  a 
jet  or  spray,  ranges  from  one-fifteenth  to  one-twentieth  the  capac- 
ity of  the  cylinder.  As  it  requires  from  22  to  30  times  as  much 
water  to  condense  steam  as  there  is  water  in  it  (according  to  the 
pressure  and  temperature),  the  air-pumps  ought  to  be  proportioned 
to  meet  the  maximum  demands.  The  right  proportions  of  air- 
pumps  for  both  jet-  and  surface-condensing  engines  may  be  found 
by  calculating  the  displacement  of  the  steam-piston,  and  that  of 
the  air-pump  for  one  minute,  and  dividing  the  former  by  the 
latter.  The  use  of  the  air-pump  in  connection  with  condensing 
engines,  as  before  stated,  is  not  an  absolute  necessity  in  all  cases, 
as,  with  a  head  of  water  having  a  fall  of  about  13  feet,  a  vacuum 
can  be  formed  and  maintained  in  the  condenser  without  an  air- 
pump,  providing  the  end  of  the  delivery-pipe  is  submerged  in  a 
tank  of  water. 

Vertical  air-pumps,  with  valves  in  their  pistons  or  buckets,  give 
the  best  satisfaction,  as,  in  that  case,  the  air  and  vapor  are  lifted 
and  forced  out  of  the  condenser,  relieving  the  exhaust  and  in- 
creasing the  vacuum.  The  capacity  of  the  openings  through  the 
valve-seats  of  air-pumps  should  be  such  that  the  maximum  flow 
of  the  water  through  them  will  not  exceed  10  feet  per  second. 
For  instance,  suppose  a  pump  of  12  ins.  stroke  to  make  50  strokes 
per  minute,  the  maximum  travel  of  the  bucket  at  midstroke  will 
be  about  2*6  feet  per  second.  Then,  as  10  H-  2*6  =  3*84,  the  capac- 
ity of  the  opening  should  not  be  less  than  one-fourth  the  area  of 
the  pumps. 


THE   ENGINEER'S   HANDY-BOOK.  355 

Air-pumps  are  frequently  very  injudiciously  located,  being 
placed  above  the  condenser;  whereas,  if  placed  below  it,  their  re- 
quirements would  be  fewer,  as  the  water  would  fall  by  gravity 
from  the  condenser  into  the  air-pump.  In  some  cases  the  air- 
pump  extends  down  through  the  condenser,  so  that  the  openings 
are  nearly  on  a  level  with  the  bottom  of  the  condenser,  which  is 
a  good  arrangement  in  every  respect,  except  that  it  necessitates  a 
long  stroke,  which  has  a  tendency  to  absorb  power. 

Independent  air-pumps,  a  cut  of  which  may  be  seen  on  page 
352,  having  an  air-cylinder  at  one  end,  the  circulating-water  cyl- 
inder at  the  other,  and  the  steam-cylinder  in  the  middle,  are  being 
very  generally  adopted  on  ocean  steamers.  The  claim  set  up  for 
them  is,  that,  as  they  are  independent  of  the  engine,  they  can  be 
worked  faster  or  slower,  according  to  the  circumstances  of  the 
case ;  that  they  absorb  none  of  the  power  of  the  engine,  and  are 
freer  from  liability  to  accident  in  stormy  weather,  or  whenever  the 
engine  races,  than  air-pumps  attached  to  the  main  engine ;  that 
they  can  be  started,  and  a  vacuum  formed,  before  the  engine  com- 
mences to  work ;  that  the  injection-water  can  be  more  easily  reg- 
ulated ;  that  they  require  no  expensive  foundation ;  that,  in  con- 
sequence of  the  water-  and  air-pistons  being  on  each  end  of  the 
steam-piston,  they  have  a  more  steady  and  uniform  motion  than 
the  ordinary  air-pump  has,  and  that,  in  consequence  of  all  their 
parts  being  accessible,  they  can  be  easily  examined,  and  any  de- 
rangement remedied  or  readjusted,  without  interfering  with  the 
working  of  the  engine. 

In  a  surface-condensing  engine,  the  air-pump  has  only  to  ex- 
tract the  water  resulting  from  the  condensed  steam  and  the  uncon- 
densed  vapor  from  the  condenser.  In  a  jet-condensing  engine, 
the  air-pump  has  to  withdraw  both  the  injection- water  and  the 
water  of  condensation ;  the  work  to  be  performed  by  the  latter 
being  from  25  to  30  times  greater  than  that  of  the  former. 

An  air-valve  is  sometimes  fitted  to  a  circulating,  reciprocating, 
or  double-acting  pump,  for  the  purpose  of  admitting  air  to  the 


856         THE  engineer's  hAndy-book. 

water  on  the  up  stroke.  As  the  valve  is  closed  against  the  dawn 
stroke,  the  air  admitted  serves  to  soften  the  shock  of  the  water. 

A  bucket  air-pump  is  a  single-acting  pump,  being,  in  fact,  a 
piston  with  a  valve  fitted  to  it,  which  closes  on  the  up  stroke  and 
opens  on  the  down,  lifting  a  quantity  of  water  equal  to  its  capacity 
at  each  stroke  of  the  engine. 

A  piston  air-pump  is  a  double-acting  pump,  the  piston  being 
eolid.  It  is  fitted  with  suction-  and  deli  very- valves,  and  dis- 
charges with  each  stroke. 

A  plunger  air-pump  is  a  double-acting  pump,  resembling  the 
bucket  air-pump,  except  that  it  has  no  head-valves,  and  that  the 
bucket-rod  is  fitted  with  a  plunger.  The  effect  of  this  is,  that  the 
plunger,  owing  to  its  displacement,  discharges  on  both  the  up  and 
the  down  stroke. 

The  double-acting  air-pump  has  both  suction-  and  delivery- 

/alves;  but  it  is  possible  with  the  single-acting  pump,  in  some 
.^ases,  to  dispense  with  either  the  one  or  the  other.  They  are 
t^enerally  made  with  pistons,  though  sometimes  with  plungers. 

An  air-pump  with  a  foot-valve  and  no  discharge-valve  would 
be  most  affected  by  a  leaky  stuffing-box ;  and,  while  the  foot-valve 
remains,  the  pump  will  draw  water,  but  if  removed,  it  will  fail  to 
work. 

An  air-pump  trunk  is  a  hollow  cylinder  attached  to  the  bucket 
or  piston,  and  working  through  a  stuffing-box.  Such  an  arrange- 
^nent  is  rendered  necessary  when  the  pump  is  worked  directly  off* 
the  crank-shaft,  or  where  it  is  located  so  close  to  the  levers, 
through  "which  the  motion  is  transmitted  from  the  engine,  as  to 
render  the  appliance  of  an  intervening  cross-head  and  links  im- 
possible. The  difference  in  the  discharge  is  equal  to  the  relative 
difference  between  the  displacement  caused  by  an  ordinary  air' 
pump  rod  and  that  caused  by  the  trunk. 


THE   engineer's  HANDY-BOOK. 


357 


The  air-pump  pet  cock  or  valve  is  generally  placed  below  the 
head-valve  and  above  the  bucket.  It  opens  with  the  down  stroke 
of  the  pump,  and  admits  air  to  act  as  a  cushion  on  the  water. 
When  the  delivery-valve  is  opened,  the  engineer  can  tell  by  its 
action  whether  the  pump  is  working  properly  or  not. 

An  air-pump  bucket  is  a  hollow  piston,  generally  made  of  brass, 
with  a  grating  in  the  top,  and  a  boss  (water-tight)  which  receives 
the  rod  in  its  centre,  from  which  strengthening  ribs  run  to  the  rim 
I  of  the  bucket.  The  outside  of  the  bucket  is  grooved  to  receive 
water-tight  packing.  The  valves,  which  are  generally  of  India- 
rubber,  and  whose  lift  is  regulated  by  a  guard  secured  by  a  nut, 
and  against  which  the  valve  is  pressed  when  the  bucket  is  on  the 
down  stroke,  are  on  the  top  of  the  grating. 

Air-pump  rods  are  generally  made  of  wrought-iron,  and  covered 
with  a  skin  of  Muntz  metal,  or  brass,  to  prevent  the  oxidization  to 
which  wrought-  or  cast-iron  rods  are  exposed. 

A  ship's  side  air-pump  discharge-valve  is  generally  a  mitred 
I    valve,  with  its  spindle  passing  through  a  gland  in  the  cover,  on 
r   which  a  weight  is  placed  to  keep  it  shut.    It  differs  from  a  stop- 
valve  in  having  a  lift  and  weight. 

There  are  numerous  contrivances  in  use  for  dispensing  with 
the  air-pump,  such  as  the  injector  condenser,  which  produces  a 
sheet  of  water  in  the  exhaust-pipe ;  but  the  necessary  arrangements 
for  operating  them  generally  cost  more  than  a  good  reliable  air- 
pump,  though  the  first  cost  of  the  former  is  less  than  that  of  the 
latter.    Besides,  the  vacuum  is  never  so  perfect  when  produced  by 
any  such  arrangement  as  when  created  by  a  close  condenser  and 
air-pump.    This  becomes  obvious,  since  we  know  that,  even  with 
the  most  perfect  mechanism,  it  is  almost  impossible  to  attain  a 
I     perfect  vacuum,  and  maintain  it  for  any  length  of  time,  as  nature 
j     abhors  a  vacuum,  as  the  atmosphere  on  the  outside  of  a  vessel 
is  constantly  endeavoring  to  equalize  any  unbalanced  pressure 
i     that  may  exist  on  the  inside. 


THE   ENGINEER'S  HANDY-BOOK. 


359 


Marine  Wrecking-Pump. 


a^d 

Water- 
Cylinder. 

Stroke. 

Gallons 

per 
Stroke. 

Capacity  per  Minute, 
at  Ordinary  Speed. 

B6 

c  . 

o  a> 

§•£ 

CQ 

be 

^-  . 

q3  Zi 

5 

6 

3J 

7 

•33 

125  strokes, 

42  gal. 

a 

4 

1 

2 

li 

4i 

10 

•69 

100 

(.i 

69 

1 

u 

2i 

2 

7 

10 

roe 

100 

166 

1 

u 

4 

3 

8 

5 

12 

1-02 

100 

IC 

102 

1 

u 

3J 

3 

8 

8 

12 

2-61 

100 

261 

1 

u 

5 

3J 

10 

6 

12 

r47 

100 

147 

u 

2 

3J 

o 

10 

10 

12 

4^08 

100 

408 

2 

5 

3^ 

360 


THE   engineer's   HANDY  -BOOK. 


The  Salinometer.* 

A  Salinometer  is  a  form  of  hydrometer  used  to  determine  the 
quantity  of  salt  contained  in  the  water  of  marJne  boilers,  and  by 

which  the  amount  of  water  necessary 
to  be  blown  out,  to  keep  the  water  in 
the  boilers  at  a  certain  density,  may  be 
ascertained.  It  is  9.  graduated  glass 
tube,  and  floats  in  th^.  water  at  a  height 
proportional  to  its  density  or  sal tn ess. 
It  is  marked  0  for  fresh  water ; 
sea-water  that  contai.'AS  1  lb.  of  salt  to 
32  lbs.  of  water;  3^3^  ^vhen  it  contains 
2  lbs.  of  salt  to  S2  lbs.  of  water,  and  so 
on.  Each  division  is  subdivided  into 
four  parts,  showing  halres  and  quarters. 
It  is  graduated  for  a  temperature  of 
200°  Fah.  A  uniform  standard  of 
temperature  is  necessary,  since  water 
must  be  taken  from  the  pressure  in  the 
boiler,  in  order  that  it  may  assume  its 
regular  temperature  under  the  pressure 
of  the  atmosphere,  because  steam  of 
different  pressures  has  diiferent  tem- 
peratures, and  a  difierence  m  tempera- 
ture will  alter  the  indications  of  the 
hydrometer. 

The  amount  of  salt  in  the  water  of 
a  boiler  may  be  ascertained  by  observ- 
ing the  degree  of  the  boiling-point  by 
means  of  a  thermometer.  To  do  this, 
a  sufficient  quantity  of  the  water  in  the  boiler  should  be  drawn 
off*  in  a  long  copper  vessel,  and  brought  to  the  boiling-point.  Then 
immerse  the  thermometer.  For  every  pound  of  salt  contained  in 
32  lbs.  of  water,  the  temperature  rises  one  degree.    Thus,  if  the 

^  See  page  651. 


The  Salinometer. 


THE   engineer's  HANDY-BOOK. 


361 


water  contains      of  salt,  it  will  boil  at  213° ;  if  y^Hj,  at  214^^ ;  if 
at  215•5^  and  Z^-,  at  216-6°. 

Salt-water,  at  the  usual  density,  contains  it-s  weight  of  salt ; 
consequently,  if  one  pound  of  salt  enters  the  boiler  with  every  32  lbs. 
of  water,  and  16  lbs.  of  that  water  be  evaporated,  the  one  pound  of 
salt  remains  in  the  proportion  of  1 : 16.  Again,  if  ^  of  the  16  lbs.  of 
water  remains  to  be  evaporated,  the  one  pound  remains  in  the  8  lbs. 
of  water.  Now,  if  these  8  lbs.  of  water  were  blown  out  of  the  boiler, 
the  salt  would  go  with  it ;  and  so  long  as  that  proportion  is  carried  out, 
the  saturation  cannot  exceed  3*^^ ;  from  which  it  is  clear  that,  to  keep 
water  at  glr,  one-fourth  must  be  blown  out ;  one-third  at  3^2,  and  at 
one-half  of  the  water  used  for  feed  must  be  blown  out. 

The  errors  in  the  hydrometer  may  be  corrected  in  the  following 
manner :  Every  10°  difference  in  temperature  will  vary  the  indi- 
cations I  of  3^2,  200°  Fah.  being  the  standard.  Then,  if  the  water 
be  10°  over  200°  Fah.,  it  will  show  \  of  less  than  its  true  density ; 
and  if  10°  below  200°  Fah.,  it  will  indicate  \  of  3^^  more.  Moreover, 
if  the  grade  be  200°  Fah.,  the  thermometer  shows  210°,  and  the  hy- 
drometer indicates  a  density  of  -/^j,  the  true  density  will  be  2^ ; 
and  if  the  temperature  be  190°,  it  will  be  1|. 

A  Salinometer  may  be  constructed  by  taking  a  long  glass  tube, 
and  inserting  in  it  sufficient  shot  to  sink  it  in  fresh  water,  marking 
the  point  at  which  the  water  stands  in  the  tube.  Then  immerse 
the  tube  in  water  containing  part  of  salt,  when  the  point  at 
which  the  water  stands  will  be  the  sea-water  mark.  Similarly 
immerse  in  water  containing  -^^^  /j,  etc.,  up  to  -J|  of  its  weight 
of  salt,  marking  off  the  respective  points  at  which  the  water  stands. 
Transfer  these  marks  to  a  scale,  and  paste  it  inside  the  bottle  in 
exactly  the  same  position  as  the  marks  on  the  bottle,  and  the  result 
is  a  good  salt'gauge.  The  temperature  must  always  be  the  same 
as  when  the  hydrometer  was  graduated. 

How  to  use  a  Salinometer.— Draw^  off  some  water  from  the 
boilers,  and  when  the  ebullition  has  ceased,  try  its  temperature  with 
a  thermometer.    If  the  temperature  exceeds  that  marked  on  the 
salinometer,  let  it  cool  till  it  reaches  that  degree ;  and  if  the  tery- 
31 


362 


THE   ENGINEER'S  HANDY-BOOK. 


perature  is  less  than  that  marked  on  the  salinometer,  it  must  be 
raised  till  it  reaches  that  degree.  Then  immerse  the  salinometer 
in  the  water  and  let  it  float ;  if  the  level  of  the  water  is  at  or 
less,  there  is  no  occasion  for  blowing  off* ;  but  if  it  exceeds  3^3^,  the 
water  must  be  changed.  The  degrees  of  temperature  usually 
marked  on  the  salinometer  are  190°,  200°,  210°.  Before  using  the 
salinometer,  it  should  be  wet  all  over  with  water. 


TABLE 

SHOWING  THE  PROPORTION  OF  SALT  IN  THE  WATER  OF  DIFFERENT  SEAS. 


PARTS  IN  1000. 

Mediterranean  Sea.... 
Atlantic  at  Equator... 

PARTS  IN  1000. 

21-60-  A 

28-30::=  3V 

33-76=  3V 
35-50= 

39-40  = 
39-42  =r/3 

41-  20  = 

42-  60  = 
385-00  = 

TABLE 

iSHOWING  THE   BOILING-POINT  OF  SALT-WATER  AT  THE  DIFFERENT  DE- 
GREES OF  DENSITY,  WHEN  THE  BAROMETER  STANDS  AT  30  INCHES. 


Fresh  water. 
Sea-water  


SATURATION. 


35 
_2_ 
3  2 
_3_ 
32 
4 

3^ 
5 

32 

6 
3^ 
Jl_ 
3  2 

8 

32 
9 
'3  2 
JO 
3  2 
il 
3  2 
12 
3  2 


BOILING-POINT. 


212  ' 

213-  2 

214-  4 

215-  5 

216-  7 

217-  9 
2191 

220-  3 

221-  5 
222.7 
223-8 

225-  0 

226-  1 


Fah. 


The  meaning  of  the  term  saturation,  in  its  relation  to  the  water 
of  marine  boilers,  means  the  quantity  of  salt  it  contains  per  gallon. 


THK  engineer's  HANDY-BOOK. 


363 


Saturation  at  means  4  oz.  salt  to  one  gallon  fresh  water ; 
5^j,  8  oz.  salt  to  one  gallon  water;  12  oz.  salt  to  one  gallon 
water,  and  so  on.  In  carrying  the  water  at  twice  as  much  is 
converted  into  steam  as  is  blown  off.    At  3^^,  the  water  blown  off 

and  that  converted  into  steam  are  equal.    At  i3_.  the  water  con- 

^  32  ' 

verted  into  steam  equals  |  of  the  water  blown  off. 

The  following  table  shows  the  method  of  regulating  the  satura- 
tion. 600  gallons  of  water,  which  is  supposed  to  contain  7200  oz. 
of  salt,  being  made  the  basis  of  the  calculation. 


Blown  out  . 

Fed  in  at      to  make 
up  for  deficiency 


Fed  in 


Fed  in 


Water 
in 

Gallons. 

Salt 
in 

Ounces. 

600 
200 

7200 
2400 

400 
200 

4800 
800 

600 
200 

5600 
steam 

400 
200 

5600 
800 

600 
200 

6400 
steam 

400 
200 

6400 
800 

600 

7200 

{  evaporated. 


I  evaporated. 


The  following  calculation  shows  the  loss  induced  by  blowing 
off  as  well  as  the  gain  derived  from  fresh-water  condensers,  pro- 


364 


THE   engineer's  HANDY-BOOK. 


viding  they  are  tight,  and  the  condensation  of  the  steam  be  per- 
fect. The  degrees  of  heat  imparted  to  the  water  converted  into 
steam  are  the  total  heat  of  the  steam  minus  the  degrees  of  heat 
in  the  feed-water.  The  heat  lost  by  blowing  off  is  the  difference 
between  the  heat  of  the  feed-water  and  the  sensible  heat  of  the 
steam. 

Rule  for  finding  the  percentage  of  loss  induced  by  blowing  off 
to  prevent  saturation. 

Multiply  loss  by  blowing  off  by  100,  and  divide  the  product  by 
the  total  degrees  of  heat  imparted  to  the  water  plus  the  heat  lost 
by  blowing  off.  (Observe  that  for  3^^,  as  twice  as  much  water  ia 
converted  into  steam  as  is  blown  off.  For  3-^,  the  amount  is  equal. 
1  3 

For  iL,  the  amount  is  |,  and  so  on.)    The  result  is  the  percentage 

of  loss. 
Example.  —  3^. 

Feed-water,  110^  ;  total  heat,  1193-45°  ;  sensible  steam,  260°. 
260°  — 110^  =  150°  heat  lost  by  blowing  off 
1193-45°     110°  =  1083-45°  total  heat. 

1083-45°x2  =  2166-9°-f  150°  =  2316-9°  total  heat  imparted, 
and  loss  by  blowing  off. 

(150°  X 100)  -T-  2316-9°  =  6-47  per  cent,  of  heat  lost  by  blow- 
ing off. 

The  Barometer. 

The  Barometer  is  an  instrument  used  for  observing  the  press- 
ure and  elasticity,  or  variations  in  density,  of  the  atmosphere. 
Its  essential  part  is  a  well  formed  glass  tube,  closed  at  one  end, 
perfectly  clear  and  free  from  flaws,  33  or  34  inches  long,  of  equal 
bore,  filled  with  pure  mercury,  and  inverted ;  the  open  end  being 
inserted  in  a  cup  partly  filled  with  the  same  metal,  so  that  the 
mercury  in  the  tube  may  be  supported  by  atmospheric  pressure. 

When  the  air  is  dry  and  light,  the  mercury  in  the  barometer 
rises ;  when  the  air  is  humid  and  lieavy,  it  falls.  When  changes 
in  the  weight  of  the  atmosphere  take  place  gradually,  they  are 


THE   ENGINEER\s   IT  A  N  J)  y  -  b  o  o  k  .  365 

imperceptible  to  huraari  sensation ;  and  if  it  were  not  for  this  instru- 
ment, it  would  be  impossible  to  estimate  accurately  atmospheric 
conditions.  If,  in  fine,  clear  weather,  a  rain-storm  is  approach- 
ing, the  increasing  humidity  of  the  atmosphere  will  be  noted  by 
the  fall  of  the  barometer  long  before  it  will  be  perceived  by  ordi- 
nary observers.  Hence,  the  condition  of  the  barometer  is  an  indi- 
cation of  not  only  the  weather  at  the  time,  but  of  that  which  is 
to  follow  during  the  course  of  several  hours.  It  is  in  a  constant 
state  of  variation,  governed  by  the  condition  of  the  air.  The  mer- 
cury in  the  barometer  stops  falling  at  30  inches  at  sea-level. 


TABLE 

SHOWING  THE  WEIGHT  OF  THE  ATMOSPHERE  PER  SQUARE  INCH  CORRE- 
SPONDING WITH  DIFFERENT  HEIGHTS  OF  THE  BAROMETER. 


Barometer 
in 
Inches. 

Atmosphere 
in 
Pounds. 

Barometer 
in 
Inches. 

Atmosphere 
in 
Pounds. 

Barometer 
in 
Inches. 

Atmosphere 
in 

Pounds. 

28-0 

13-72 

29-1 

14-26 

30-1 

14-75 

28-1 

13-77 

29-2 

14-31 

30-2 

14-80 

28-2 

13-82 

29-3 

14-36 

30-3 

14-85 

28-3 

13-87 

29-4 

14-41 

30-4 

14-90 

28-4 

13-92 

29-5 

14-46 

30-5 

14-95 

28-5 

13-97 

29-6 

14-51 

30-6 

15-00 

28-6 

14-02 

29-7 

14-56 

30-7 

1505 

28-7 

14-07 

29-8 

14-61 

30-8 

15-10 

28-8 

14-12 

29-9 

14-66 

30-9 

15-15 

28-9 

14-17 

30-0 

14-70 

31- 

15-19 

290 

14-21 

Thermometei'S. 

The  Thermometer  is  an  instrument  for  measuring  variations  of 
heat  or  temperature.  It  consists  of  a  bulb  and  glass  stem  of  uni- 
form bore.  A  sufficient  quantity  of  mercury  having  been  intro- 
duced, it  is  boiled,  to  expel  the  air  and  moisture,  and  the  tube 
is  then  hermetically  sealed.  '  The  properties  of  mercury  which 
render  it  preferable  to  all  other  liquids  are  these:  it  supports, 
31^ 


366 


THE   ENGINEER'S  HANDY-BOOK. 


before  it  boils,  more  heat  than  any  other  fluid,  and  endures  a 
greater  cold  than  would  congeal  most  other  liquids. 

The  standard  points  are  ascertained  by  immers- 
ing the  thermometer  in  melted  ice  and  in  the  steam 
of  water  boiling  under  the  pressure  of  14*71bs.  on  the 
square  inch,  and  marking  the  positions  of 
the  top  of  the  column.  The  interval 
between  those  points  is  divided  into  the 
proper  number  of  degrees,— 100  for  the 
Centigrade  scale,  180  for  Fahrenheit's, 
and  80  for  Reaumur's. 

The  word  "  zero  "  is  of  Arabic  origin, 
and  means  empty ;  hence  nothing.  Ab- 
solute zero  is  a  temperature  which  is  fixed 
by  reasoning,  although  no  opportunity 
ever  occurs  for  observing  it.  It  is  the 
temperature  corresponding  to  the  disap- 
pearance of  gaseous  elasticity;  or,  in 
other  words,  the  point  where  gas  would 
become  a  solid,  as  where  water  becomes 
ice.    This  temperature  is  called  zero  in 

The  Hotwen    reference  to  all  the  erases,  and  the     The  Uptake 
Thermometer.  «  ^,      ,     i°  ^,  Thermometer, 

positions  01  the  absolute  zero  on  the 

ordinary  scales  would  be 

Reaumur's  scale  219*2  belof^  0^ 

Centigrade  244 

Fahrenheit    .       .       .       .       .       .  461-22  " 

Rules  for  Comparing  Degrees  of  Temperature  Indicated  by  Dif- 
ferent Thermometers.  1.  Multiply  degrees  of  Centigrade  by  9  and 
divide  by  5;  or  multiply  degrees  of  Reaumur  by  9  and  divide  by  4. 
Add  32  to  the  quotient  in  either  case,  and  the  sum  is  degrees  Fah- 
renheit. 2.  From  degrees  of  Fahrenheit  subtract  32 ;  multiply  the 
remainder  by  5,  and  divide  by  9  for  degrees  Centigrade ;  or  mul- 
tiply by  4,  and  divide  by  9  for  degrees  Reaumur.  The  abbrevia- 
tion for  Fahrenheit  is  "  Fah." ;  for  degree,  °. 


THE   ENGINEER\s  HANDY-BOOK. 


567 


Marine  Steam-Engine  Register. 


This  instrument  is  designed  for  application  to  marine  steam- 
engines.  It  consists  of  a  circular  box  faced  with  a  dial,  in  which 
are  cut,  side  by  side, 
six  or  more  slots, 
through  which  may 
be  seen  the  numbers 
representing  the 
revolutions  of  the 
engine.  This  dial 
is  called  the  '^coun- 
ter "  or  register/' 
which  is  worked 
by  an  attachment 
to  any  suitable  part 
of  the  engine,  from 
which  a  vibratory 
motion  may  be 
communicated  to 
an  arm  attached  to 
a  central  horizontal 
shaft  placed  paral- 
lel to  the  dial,  into 
the  ends  of  which 
is  fixed  a  frame  carrying  a  small  shaft,  parallel  to  the  former,  to 
which  six  arms  are  attached  in  such  a  way  that  the  right  arm  may 
fall  without  the  others,  but  cannot  rise  without  carrying  all  the  rest 

This  framework,  with  the  pall-shaft,  etc.,  by  the  motion  of 
the  arm  attached  to  the  engine,  describes  an  arc  of  36°,  or 
of  a  circle.  The  ends  of  the  palls,  respectively,  rest  on  and 
slide  over  6  cylinders  placed  side  by  side  on  the  central  shaft,  all 
of  which  move  in  the  same  direction,  and  are  numbered  from 
right  to  left.  On  the  right-hand  edge  of  each  cylinder  are  cut 
10  slots,  and  on  the  left  hand  only  one  slot,  which  are  of  such  a 


368 


THE   ENGINEER'S  HANDY-BOOK. 


size  as  to  admit  the  end  of  one  of  the  palls.  Then.,  on  the  bjick 
motion  of  the  framework,  etc.,  the  pall  is  carried  back  until  it 
drops  in,  when  the  forward  motion  carries  with  it  the  cylinder  so 
locked. 

In  the  spaces  between  the  laps,  in  each  cylinder,  and  opposite 
to  one  of  the  slots  in  the  dial  face,  the  numbers  1,  2,  3,  etc., 
to  0,  are  engraved  at  equal  distances  around  the  circumference. 
The  palls  are  placed  one  over  each  of  the  slots,  so  that  the 
pall  can  fall  into  the  inner  cylinder  only  when  the  slot  in  the 
outer  one  comes  directly  under  it.  As  this  occurs  only  once 
in  a  whole  revolution,  and  as  the  motion  of  the  palls  is  only 
through  one-tenth  of  a  circle,  it  follows  that  cylinder  No.  2  can 
only  be  moved  through  one-tenth  of  its  circumference  after  cyl- 
inder No.  1  has  moved  a  whole  revolution,  or  ten  times  that  space, 
and  so  on.  Thus,  if  the  figures  on  No.  1  represent  units,  those  on 
No.  2  will  be  tens,  on  No.  3,  hundreds,  etc.  It  will  be  observed 
that  every  revolution  of  the  engine  insures  one-tenth  of  cylinder 
No.  1  to  move  round,  inasmuch  as  the  ten  slots  in  its  right-hand 
edge  are  not  covered  by  any  other  cylinder,  as  is  the  case  with 
the  others. 

Rule  /or  Finding  the  Number  of  Revolutions  the  Engine  has 
made  during  the  Voyage, 

Subtract  the  number  at  which  the  counter  stood  at  the  beginning 
of  the  voyage  from  that  which  is  indicated  at  the  end  of  it ;  the  re- 
mainder will  be  the  number  of  revolutions  made  during  the  voyage. 

To  Reduce  the  Time  the  Counter  has  been  Working  into  Minutes. 

Multiply  the  days  by  24,*  the  product  will  be  the  hours ;  multi- 
ply this  by  60,t  the  result  will  be  the  minutes  during  which  the 
counter  has  been  working,  or  divide  the  number  of  revolutions  by 
the  minutes  the  counter  has  been  working ;  the  quotient  will  be  the 
average  number  of  revolutions  made  by  the  engine  per  minute. 


^  24  hours  being  equal  to  one  day. 


t  Ab  60  minutes  =  1  hour. 


THE   ENGlisTEER'S    HANDY-BOOK.  369 

Spring-,  Mercury-5  Syphon-,  and  Vacuum-Gauges.* 

Figure  I  shows  an  inside  view  of  the  Lane  spring  steara- 
^auge.  As  may  be  observed,  it  consists  of  a  hollow  brass  tube, 
a  lever,  connecting- 
link,  sector,  pinion, 
and  pointer.  Its  oper- 
ation is  as  follows: 
Pressure  is  exerted 
in  the  tubes.  A,  A, 
through  the  nipple, 
the  effect  of  which 
IS  to  elongate  or 
Btraighten  it.  The 
consequence  is,  that 
the  link,  0,  draws  the 
lever,  E,  and  the  sec- 
tor, Fy  which  moves 
the  pinion,  which  is 
not  shown,  but  which 
carries  the  pointer,  G, 
The  higher  the  pressure,  the  more  the  tubes  will  be  expanded  or 
elongated,  and  the  higher  the  pointer  will  be  carried  up.  As  the 
pressure  decreases,  the  tubes  have  a  tendency  to  contract,  and  the 
pointer  again  assumes  its  natural  position  at  zero. 

Fig.  2  (page  370)  represents  the  Bourdon  spring  steam-gauge. 
It  consists,  as  in  the  case  of  the  Lane,  of  a  hollow  metal  tube,  con- 
necting-link, sector,  pinion,  coil-spring,  and  hand  or  pointer.  As 
will  be  seen,  though  the  mechanism  is  reversed,  the  principle  is 
the  same  as  in  the  Lane  gauge.  The  pressure  exerted  in  the 
hollow  tube,  G,  has  a  tendency  to  expand  or  elongate  it ;  the  result  * 
of  which  is,  that  the  link,  H,  draws  the  sector,  J,  (which  swings  on 
the  stud  I)  to  the  right,  the  upper  end  of  which  turns  the  pinion, 
K,  which  carries  the  pointer  to  the  right  also.    A  coil-spring  is 

*  *See  Dage  658 


Fig.  1. — Inside  View. 


370  THE  ENGINEER'S  HANDY-BOOK. 

attached  to  the  stud,  which  carries  the  pointer  to  assist  in  bring- 
ing it  back  to  a  state  of  rest,  as  the  pressure  decreases. 

The  advantages  of  spring-gauges  are,  that  they  are  light,  cheap, 
and  simple,  and  are  not  affected  by  jar  or  jolting;  their  disad- 
vantages are,  liability  to  corrode,  and  the  spring  losing  its  ten- 
sion ;  they  require  to  be  tested  and  corrected  at  least  once  a  year. 
When  steam-gauges  of  any  kind  are  set  up,  the  end  of  the  pipe 
next  the  gauge  should  invariably  be  filled  with  cold  water.  The 
steam  should  never  be  allowed  to  act  directly  on  a  steam-gauge 

when  located  in  cold 
situations,  where  they 
are  liable  to  freeze. 
The  valve  on  the  boil- 
er should  be  closed, 
and  the  drip  attached 
to  the  gauge  opened, 
in  order  to  allow  the 
water  to  run  out.  The 
drip  on  the  gauge 
should  be  closed  be- 
fore the  steam  is 
turned  in  from  the 
boiler,  in  order  that 
suflScient  steam  may 
be  condensed  in  the 
pipe  to  furnish  the 
quantity  of  water  necessary  to  keep  the  steam  from  striking  the 
gauge.  • 

The  spring-gauge  can  also  be  used  as  a  vacuum-gauge,  by  re- 
versing the  application  of  the  pressure,  which  has  a  contrary  effect 
on  the  tube.  For  instance,  as  exhaustion  takes  place  in  the  tube, 
its  power  of  resisting  the  pressure  of  the  surrounding  atmosphere, 
which  acts  upon  it,  varies  also,  and  it  consequently  again  coils  under 
that  pressure  in  regular  ratio  with  its  variation,  and  indicates  the 
degree  of  vacuum  in  the  condenser. 


Fig.  2.  —  Inside  View. 


THE   engineer's  HANDY-BOOK. 


371 


A  siphon-gauge  is  a  bent  tube,  inverted,  and  partially  filled 
with  mercury.  The  orifice  of  the  short  leg  is  connected  with  the 
boiler,  and  the  long  leg  is  open  to  the  atmosphere.  The  steam 
pressing  upon  the  mercury  in  the  short  leg  with  greater  force 
than  the  pressure  of  the  atmosphere,  causes  the  mercury  in  the 
other  leg  to  rise,  and  indicates  the  excess  of  pressure  above  the 
atmosphere.  To  the  amount  shown  by  the  gauge  must  be  added 
the  pressure  of  the  at- 
mosphere. Thus,  if  a 
siphon-gauge  shows 
15  lbs.  pressure,  the 
boiler-pressure  is  30 
lbs. 

A  mercurial  gauge, 

for  high  -  pressure 
steam  -  engines,  con- 
sists of  a  glass  tube 
open  at  the  lower 
end,  and  closed  at  the 
top,  containing  air  in 
its  ordinary  state.  Its 
lower  end  is  placed 
in  a  cistern  of  mer- 
cury. When  the  cock 
is  opened,  the  steam 
passes  through,  forc- 
ing the  mercury  up  the  glass  tube,  thereby  compressing  the  air 
in  the  tube  above  the  mercury.  When  the  air  is  compressed  to 
one-half  its  original  space,  the  pressure  is  doubled ;  to  one-third, 
it  is  trebled ;  to  one-fourth,  it  is  quadrupled,  etc. 

A  barometer-gauge  is  a  tube  of  glass,  more  than  30  inches  long, 
closed  at  one  end,  and  filled  with  mercury,  then  inverted  so  that 
the  lower  or  open  end  will  be  immersed  in  a  cistern  of  mercury, 
when  the  mercury  in  the  tube  will  sink,  rising  in  the  basin  until 
Its  weight  balances  the  pressure  of  the  atmosphere,  which,  by  its 


Figr.  3. -The  Springr  Steam-Gauge. 


872         THE  engineer's  handy-book. 


elasticity,  is  endeavoring  to  force  the  mercury  up  the  tube.  The 
mercury  in  the  tube  will  be  found  to  stand  about  30  inches  higher 
than  the  level  in  the  basin,  varying  slightly,  according  to  the  state 
of  the  atmosphere. 

The  scale  of  a  barometer-gauge  may  be  explained  as  follows: 
As  30  inches  of  mercury  press  down  with  the  same  force  as  the 
atmosphere,  say  15  lbs.  per  square  inch,  two  inches  of  mercury 
correspond  to  one  pound  of  pressure,  and  a  scale  of  inches  meas- 
ured from  the  mercury  in  the  cup  upwards  must  be  fixed  near 
the  glass  tube.  As  the  vacuum,  while  the  engine  is  working,  may 
be  supposed  to  be  good,  the  scale  need  only  be  marked  to  a  few 
inches  below  30  inches,  every  fall  of  two  denoting  one  pound  of 
pressure  in  the  condenser. 

The  sources  of  error,  in  estimating  the  vacuum  by  this  gauge, 
arise  from  the  following  two  facts :  That  the  pressure  of  the  at- 
mosphere, or  the  mercury  in  the  cup,  is  liable  to  change.  That 
the  gradations  on  the  scale  are  marked,  on  the  supposition  that 
the  level  of  the  mercury  is  stationary ;  because  it  is  from  this 
level  that  the  scale  commences.  Therefore  a  fixed  scale  must  be 
erroneous,  on  account  of  the  sinking  of  the  mercury  in  the  cup 
as  it  rises  in  the  tube. 

The  first  source  of  error  may  be  corrected  by  observing  the 
actual  height  of  a  weather  barometer,  and  subtracting  it -from  the 
height  as  shown  by  the  gauge.  This  will  be  correct,  if  a  tube  of 
a  standard  diameter  is  used.  This  error  may  be  corrected  by  a 
short  gauge,  similar  to  what  a  weather  barometer  would  be  if  it 
were  enclosed  in  a  space,  communicating  with  the  condenser.  In  that 
event,  before  a  vacuum  is  created,  the  mercury  would  stand  as 
high  in  the  glass  tube  as  in  the  weather  barometer.  On  creating 
a  vacuum,  thus  taking  off*  the  pressure  from  the  mercury  in  the 
cistern,  the  mercury  would  fall  in  the  tube.  In  this  instrument, 
the  less  the  height  of  the  mercury  the  better  the  vacuum. 

The  second  source  of  error  may  be  obviated  by  having  a  mov- 
able instead  of  a  fixed  scale,  so  that  its  lower  end  might  always 
be  kept  in  contact  with  the  surface  of  the  mercury  in  the  cup. 


THE   ENaiNEEU\s  HANDY-BOOK. 


373 


A  siphon -gauge,  such  as  has  been  spokeu  of,  may  be  used  as  a 
vacuum-gauge.  When  so  used,  it  is  necessary  to  connect  the  long 
leg  with  the  condenser,  placing  a  stick  in  the  short  leg.  In  this 
case  the  scale  would  require  to  be  graduated  directly  contrary 
to  that  for  steam.  The  state  of  the  atmosphere  will  affect  the 
gauge.  The  pressure  in  the  steam-boiler  may  be  ascertained  by 
the  temperature,  by  the  safety-valve,  or  by  the  steam-gauge. 

I  The  Mariner's  Compass. 

y  The  object  of  the  mariner's  compass  is  to  enable  travellers  to 
steer  their  course  with  certainty  from  one  location  to  another. 
The  needle  is  understood  to  point  to  the  north,  and  the  other 
points,  east,  west,  etc.,  are  easily  found.  In  certain  parts  of  the 
world,  however,  the  needle  does  not  point  to  the  north,  but  is  drawn 
to  the  right  or  left  of  true  north.  This  is  called  the  variation  of  the 
compass,  and  must  be  known  accurately  by  the  navigator,  in  order 
to  correct  and  steer  the  right  course.  For  instance,  in  crossing 
the  Atlantic  Ocean,  the  variation  of  the  compass  amounts  in  sail- 
ing vessels  to  2J  or  2J  points  westerly,  and  the  course  steered  must 
be  corrected  accordingly.  If  a  due  east  course  is  desired,  the 
vessel  must  be  steered  2  J  or  2i  points  south. 

Off  the  Cape  of  Good  Hope,  the  variation  of  the  compass  in 
ships  bound  to  India  or  Australia  is  2|  points  easterly,  and,  in 
order  to  make  a  due  east  course,  it  is  necessary  to  steer  2|  to  the 
north,  or  left  of  her  course ;  while  towards  the  equator  there  is 
hardly  any  perceptible  variation  of  the  compass  at  all.  The  best 
means  of  finding  out  how  much  the  compass  varies  in  different 
parts  of  the  world  is  by  observations  of  the  sun  taken  with  the 
compass,  and  the  difference  between  the  true  and  magnetic  compass 
is  the  variation,  which  must  be  applied  as  a  correction  to  the  course 
steered.  In  iron  ships  or  steamers,  the  deviation  must  be  considered 
as  well  as  the  variation.  This  is  due  to*the  local  attraction  caused 
by  the  iron,  and  must  be  carefully  understood  before  steamers  or 
iron  ships  go  to  sea.  Before  a  vessel  proceeds  on  her  first  voyage, 
the  compass  must  be  carefully  swung  and  magnets  fixed  to  th*' 
>^^ck. 


374 


THE  engineer's  HANDY-BOOK. 


TABLE 

OP  RHUMBS,  OR  POINTS  OF  THE  COMPASS. 


Points. 

Angles. 

NORTH. 

NORTH. 

SOUTH. 

SOUTH. 

i 

i 

4 

O          '  '• 

2  48  45 
5  37  30 
8  26  15 

N  i  E 
N  2  E 
N  f  E 

N  i  W 
N  i  W 
N  f  W 

S  i  E 
S  i  B 
S  J  E 

s  i  w 

S  2  W 

s  f  w 

1 

U 
H 
If 

1115  0 

14  3  45 
16  52  30 
19  41  15 

N  by  E 

N  by  E  }  E 
N  by  E  i  E 
N  by  E  f  E 

N  by  w 
N  by  w  i  w 
N  by  w  i  w 
N  by  w  1  w 

s  by  E 
s  by  E  i  E 
s  by  E  2  E 
s  by  E  J  E 

s  by  w 
s  by  w  ?  w 
s  by  w  2  w 
s  by  w  f  w 

2 

2i 
2i 
2f 

22  30  0 

25  18  45 
28   7  30 
30  56  15 

NNE 
NNE  i  E 
NNE  i  E 
NNE  f  E 

NNW 
NNW  ?•  W 
NNW  2  W 
NNW  f  W 

SSE 
SSE  i  E 
SSE  i  E 
SSE  J  E 

ssw 
ssw  k  w 
ssw  2  w 
ssw  1  w 

3 

Si 
3i 
3i 

33  45  0 

36  33  45 
39  22  30 
42  11  15 

NE  by  N 

NE  f  N 
NE  i  N 
NE  i  N 

NW  by  N 
'    NW  4  N 
NW  i  N 
NW  4  N 

SE  by  s 

SE  f  S 
SE  J  S 
SE  }  S 

sw  by  s 
sw  f  s 
sw  2  s 
sw  i  s 

4 

4^ 
4J 
4f 

45  0  0 

47  48  45 
50  37  30 
53  26  15 

NE 
NE  J  E 
NE  i  E 
NE  f  E 

NW 
NW  i  W 
NW  i  W 
NW  f  W 

SE 
SE  i  E 
SE  }  E 
SE  J  E 

sw 
sw  i  w 
sw  2  w 
sw  f  w 

5 

5i 
5i 
5i 

56  15  0 

59   3  45 
61  52  30 
64  41  15 

NE  by  E 

ENE  1  N 
ENE  i  N 
ENE  }  N 

NW  by  w 

WNW  f  N 
WNW  i  N 
WNW  i  N 

SE  by  E 

ESE  f  S 
ESE  i  8 
ESE  }  S 

sw  by  w 
wsw  i  s 

WSW  2  s 

wsw  i  s 

6 

6} 
6} 
6f 

67  30  0 

70  18  45 
73  7  30 
75  56  15 

ENE 
ENE  i  E 
ENE  i  E 
ENE  1  E 

WNW 
WNW  i  W 
WNW  i  W 
WNW  J  W 

ESE 
ESE  i  E 
ESE  i  E 
ESE  f  E 

wsw 
wsw  i  w 
wsw  2  w 
wsw  f  w 

7 

7} 
7J 
7f 

78  45  0 

81  33  45 
84  22  30 
87  11  15 

E  by  N 
E'f  N  ^ 

E  i  N 
E  i  N 

w  by  N 

W  f  N 
W  i  N 
W  i  N 

E  by  s 

E  J  S 
E  ^  S 

w  by  s 
wis 
wis 
wis 

I  

90  0  0 

EAST. 

WEST. 

EAST. 

WEST. 

THE   engineer's    II  A  N  I)  Y  -  B  O  O  K  . 


cc  o 


O 
O 
O 

CO 

CO 


o 

o 

o 

o 

o 

o 

o 

tH' 

CO 

co^ 

'co^ 

(xT 

co" 

cT 

CD 

CO 

rH 

O 

o 

o 

o 

o 

o 

o 

o 

o 

QO 

CO 

ZD 

C5 

c» 

co" 

7—1 

-2 


376         THE  engineer's  handy-book. 

Technical  Terms  and  Definitions  Used  in  Navigation. 

Apparent  altitude. — The  apparent  altitude  is  the  observed 
altitude,  corrected  for  the  indicated  error  of  the  instrument,  and 
dip  of  the  horizon. 

Meridian  altitude.  — The  meridian  altitude  is  the  highest  alti- 
tude a  celestial  object  attains  on  the  meridian  of  the  observer. 

Observed  altitude.  —  The  observed  altitude  is  the  altitude  of 
a  celestial  object  above  the  horizon  dneasured  by  a  sextant  or 
quadrant. 

True  altitude. — The  true  altitude  is  the  apparent  altitude  cor- 
rected for  refraction  and  parallax. 

Amplitude. — The  amplitude  is  the  arch  of  the  horizon  con- 
tained between  the  centre  of  the  celestial  object,  when  rising  or 
setting,  and  the  east  or  west  points  of  the  horizon,  measured  from 
the  east  when  rising,  and  from  the  west  when  setting. 

Azimuth.  —  An  azimuth  is  the  angle  at  the  zenith  contained 
between  the  vertical  circle  passing  through  the  centre  of  the  ce 
lestial  object,  and  of  the  meridian  of  the  place. 

Course.  — The  course  is  the  direction  steered  by  compass. 

Magnetic  course. — The  magnetic  course  is  the  compass  coursa 
yX)rrected  for  deviation  of  the  compass. 

True  course. — The  true  course  is  the  compass  course  cor- 
x^ected  for  variation  and  deviation  of  the  compass. 

Course  made  good.  —  The  course  made  good  is  the  compass 
course  corrected  for  deviation,  variation,  leeway,  and  set  of  the 
current,  and  is  the  ship's  real  track  on  the  ocean. 


THE   engineer's  HANDY-BOOK. 


377 


Variation  of  the  compass.  —  The  variation  of  the  compass  is 
the  angle  between  the  true  north  and  the  magnetic  north.  There 
are  only  few  places  where  the  needle  points  exactly  to  the  true 
north.  When  it  points  to  the  eastward  of  the  true  north,  it  is 
easterly  variation ;  but  when  the  north  point  of  the  needle  is  at- 
tracted to  the  westward  of  north,  it  is  called  westerly  variation. 

Deviation  of  the  compass.  —  The  deviation  of  the  compass  is 
the  angle  between  the  compass  north  and  the  magnetic  north,  and 
is  produced  by  the  local  attraction  of  the  ship's  iron  on  her  com- 
passes. 

Declination. —  The  declination  is  the  distance  a  celestial  object 
is  north  or  south  of  the  equinoctial,  measured  on  a  meridian. 

Eppop  of  the  compass.  —  The  error  of  the  compass  is  the  va- 
riation and  deviation  combined. 

Dead  peciconing.  —  The  dead  reckoning  is  the  method  of  as- 
certaining the  ship's  position  by  the  courses  steered  and  distance 
sailed,  as  shown  in  the  following  pages  under  the  head  of  the 
Day's  Work.  This  is  liable  to  many  errors,  such  as  bad  steering, 
unknown  currents,  improper  allowances  made  for  distance  run, 
and  often  fails  to  give  the  ship's  true  position. 

Depaptupe. — The  departure  is  the  distance  in  miles  made  good 
by  a  ship,  east  or  west ;  when  a  ship  sails  due  north  or  south,  she 
makes  no  departure. 

Taking  a  depaptupe. — When  bearings  are  taken  of  some  head- 
land or  other  known  object,  before  a  ship  leaves  the  land,  it  is 
called  taking  a  Departure. 

Distance. — Distance  is  the  distance  between  two  places  or  po- 
sitions, or  the  distance  sailed  by  a  ship  on  a  certain  course,  meas- 
ured in  nautical  miles. 

Polar  distance. — The  polar  distance  is  the  distance  of  a  ca- 

32* 


378 


THE   engineer's  HANDY-BOOK. 


lestial  object  from  the  elevated  pole,  and  is  found  by  subtracting 
the  declination  of  the  object  from  90^,  when  the  latitude  and  the 
declination  are  of  the  same  name,  but  by  adding  the  declination  to 
90°,  when  they  are  of  contrary  names. 

Ecliptic.  — The  ecliptic  is  the  apparent  annual  path  of  the  sun 
in  the  heavens. 

Equator. — The  equator  is  a  great  circle  passing  round  the 
earth,  90  degrees  from  the  poles,  and  dividing  it  into  two  equal 
parts  or  hemispheres,  called  the  Northern  and  Southern  Hemi- 
spheres. At  all  places  on  the  Equator,  the  sun  rises  and  sets  at 
six  o'clock  all  the  year  round. 

Visible  horizon. — The  visible  horizon  is  the  circle  that  bounds 
the  observer's  view  at  sea,  where  sky  and  water  appear  to  meet. 

Dip  of  the  horizon.  —  The  dip  of  the  horizon  is  the  angle  be- 
tween the  true  and  visible  horizon,  and  is  a  correction  which  must 
be  subtracted  from  all  altitudes. 

Hour  angle  of  a  celestial  object.  —  The  hour  angle  of  a  ce- 
lestial object  is  the  angle  at  the  pole  between  the  meridian  of  the 
observer  and  that  of  the  celestial  object. 

Latitude. — Latitude  is  distance  north  or  south  from  the  Equator, 
measured  in  degrees,  minutes,  and  seconds  on  a  meridian ;  a  place 
or  position  is  in  north  or  south  latitude,  according  as  it  is  north  or 
south  of  .the  Equator;  a  degree  of  latitude  is  60  nautical  miles 
of  6082  feet. 

Parallels. — Parallels  of  Latitude  are  small  circles  parallel  to 
the  Equator,  running  round  the  earth  east  and  west.  Two  places 
situated  on  one  of  these  circles  are  said  to  be  in  the  same  parallel 
of  latitude. 

Difference.  —  Difference  of  Latitude  is  the  distance  a  ship 


THE   ENGINEER'S  HANDY-BOOK. 


379 


makes  good  in  a  north  or  south  direction.  When  two  places  or 
positions  are  on  the  same  side  of  the  Equator,  that  is,  in  north  or 
south  latitude,  their  difference  of  latitude  is  found  by  subtracting 
the  lesser  latitude  from  the  greater  ;  when  two  places  or  positions 
are  on  the  opposite  sides  of  the  Equator,  that  is,  when  one  is  in 
north  latitude,  and  the  other  in  south  latitude,  their  difference  of 
latitude  is  found  by  adding  the  latitudes  together. 

Leeway.  —  The  leeway  is  the  angle  between  the  ship's  true 
course  and  her  path  through  the  water ;  starboard  tack  allows  lee- 
way to  the  left  hand ;  port  tack  allows  it  to  the  right  hand. 

Longitude. —  Longitude  is  the  degrees,  minutes,  and  seconds  a 
place  or  position  is  east  or  west  of  the  first  meridian,  measured  on 
the  Equator.  Most  nations  adopt  the  Meridian  of  Greenwich  ob- 
servatory in  England  as  the  first  meridian.  Thus  the  longitude 
of  a  place  or  position  is  called  east  or  west  of  the  Meridian  of 
Greenwich,  reckoned  up  to  180  degrees,  which  is  the  opposite  me- 
ridian to  Greenwich,  or  one-half  of  the  circumference  of  the 
earth.  Longitude  is  also  reckoned  by  time, —  hours,  minutes,  and 
seconds, —  each  hour  being  equal  to  15  degrees  of  longitude,  as  the 
sun,  which  regulates  the  time,  returns  to  the  same  meridian  once 
in  every  24  hours.  Thus  15  degrees  multiplied  by  24  hours 
makes  360  degrees,  the  entire  circumference  of  the  earth. 

To  reduce  longitude  into  time.  —  Divide  the  number  of  de- 
grees, seconds,  and  minutes  by  15,  and  the  quotient  will  be  the 
time. 

Degrees  of  Longitude. — The  degrees  of  longitude  are  of  the 
same  length  at  the  Equator  as  a  degree  of  latitude,  viz.,  60  nau- 
tical miles ;  but  as  the  meridians  contract,  and  the  distance  be- 
tween them  decreases  gradually  the  farther  you  go  north  or  south, 
until  they  meet  at  the  poles,  it  is  evident  that  the  space  contained 
in  a  degree  of  longitude  becomes  less  the  farther  north  or  south 
the  distance  travelled.  Thus  in  latitude  60°  north  or  south,  30 
miles  of  departure  is  equal  to  a  degree  of  longitude.    It  will  be 


380 


THE   ENGINEER'S  HANDY-BOOK. 


seen  that  if  a  vessel  sails  60  miles  east  or  west  in  the  parallel  of 
60°  north  or  south,  she  will  make  two  degrees  of  longitude ;  in 
latitude  of  70°  north  or  south,  60  miles  is  equal  to  nearly  three 
degrees  of  longitude. 

Difference  of  longitude.  —  The  difference  of  longitude  is  the  dif- 
ference in  degrees,  minutes,  and  seconds  which  one  place  or  position 
is  east  or  west  of  another  ;  when  two  places  or  positions  are  on  the 
same  side  of  the  Meridian  of  Greenwich  east  or  west,  their  dif- 
ference of  longitude  is  found  by  subtracting  the  less  from  the 
greater.  When  they  are  on  opposite  sides  of  the  Meridian  of 
Greenwich,  that  is,  one  in  east  longitude  and  one  in  west  longi- 
tude, their  difference  of  longitude  is  found  by  adding  the  two  to- 
gether. When  one  longitude  is  east  and  the  other  west,  and  on 
being  added  together  the  sum  exceeds  180  degrees,  it  must  be  sub- 
tracted from  360  degrees  to  get  the  difference  of  longitude. 

Meridian.  — A  meridian  is  a  circle  passing  through  both  poles, 
and  crossing  the  Equator  at  right  angles  All  places  situated  on 
this  circle  are  on  the  same  meridian,  or  in  the  same  longitude 
north  or  south  of  each  other. 

Parallax.  — The  parallax  is  the  difference  between  the  altitude 
of  a  heavenly  body  observed  on  the  surface  and  what  it  would  be 
if  taken  at  the  centre  of  the  earth. 

Poles. — The  poles  are  the  extremities  of  the  earth's  axis; 
these  are^  90  degrees  north  and  south  of  the  Equator,  and  are 
called  the  North  and  South  Poles. 

Port  side.  —  The  term  port  side  is  used  to  designate  the  left 
hand  side  of  the  ship  looking  towards  the  bow. 

Refraction.  — The  refraction  is  the  difference  between  the  real 
and  apparent  places  of  heavenly  bodies,  as  affected  by  the  atmos- 
phere. 


THE   ENGINEER^S  HANDY-BOOK. 


381 


Right  ascension.  — The  right  ascension  is  the  distance  a  ce- 
estial  object  is  east  of  the  first  point  of  Aries,  measured  on  the 
equinoctial. 

Semi-diametep.  — The  semi-diameter  is  half  the  diameter  of 
the  sun  or  moon.  It  is  given  for  each  day  in  the  Nautical  Al- 
manac, and  must  be  applied  to  all  altitudes  of  the  sun  or  moon  to 
get  the  true  central  altitude.  If  the  lower  limb  is  observed,  it 
must  be  added;  if  the  upper  limb,  subtracted,  and  vice  versd. 

Starboard  side.  —  The  term  starboard  side  is  employed  to  des- 
ignate the  right  hand  side  of  a  ship  looking  towards  the  bow. 

Augmentation.  — The  augmentation  of  the  Moon's  semi-diam- 
eter  is  a  correction  to  be  added  to  the  semi-diameter,  as  taken 
from  the  Nautical  Almanac,  on  account  of  the  moon  being  nearer 
to  the  observer  when  above  the  horizon  than  when  in  the  horizon. 

Tropics.— The  Tropics  are  that  portion  of  the  earth  situated 
between  23J°  north  and  23}°  south  latitudes. 

Civil  time.— Civil  time  is  reckoned  from  midnight  to  noon,  then 
called  A.  M. ;  and  from  noon  to  midnight,  then  called  p.  m.  The 
civil  day  commences  at  midnight ;  the  nautical  or  sea  day  com- 
mences at  noon,  twelve  hours  before  the  civil  day. 

Astronomical  time.— Astronomical  time  is  reckoned  from  noon 
to  noon  continuously,  from  0  hour  to  24  hours. 

Sidereal  time.— Sidereal  time  is  the  hour-angle  of  the  first 
point  of  Aries,  west  of  the  meridian. 

Apparent  time.— Apparent  time  is  time  reckoned  by  the  sun, 
which  is  subject  to  continual  variations,  and  requires  correction 
for  astronomical  purposes. 

Mean  time.— Mean  time  is  time  regulated  by  the  average  or 
mean,  instead  of  the  unequal  or  apparent,  motion  of  the  sun, 


382 


THE   engineer's  HANDY-BOOK. 


aud  is  such  as  would  be  shown  by  the  sun  if  it  moved  uniformly 
in  the  equinoctial. 

Equation  of  time.  —  The  equation  of  time  is  the  difference  be- 
tween apparent  and  mean  time,  is  found  in  the  Nautical  Almanac 
for  each  day,  and  is  used  for  reducing  apparent  time  to  mean 
time. 

Zenith  distance.  — The  zenith  distance  is  the  distance  a  celes> 
tial  object  is  from  the  zenith,  or  the  point  overhead. 

TABLE 

OF  THE  MILE  AS  MEASURED  BY  VARIOUS  NATIONS. 


The  English  mile  is  1760  yds. 

The  Scotch        "     1984  " 

The  Irish          "      2240  " 

The  German      "      8106  " 

The  Dutch  and  Prus- 
sian mile  is  .    .    .  6480  " 

The  Italian  mile  is  .  1766  " 

The  Vienna  post  mile 

is                        8296  " 

The  Swiss  mile  is    .  9153  " 


The  Swedish  and 

Danish  mile  is  .  7341*5  yds. 

The  Arabian  "     .  2143  " 
The  Roman  mile  is 

1628  or  2025  " 
The  Werst  mile  is 

1167  or  1337  " 

The  Tuscan  mile  is  1808  " 

The  Turkish    "     1826  " 

The  Flemish    "     6869  " 


The  British  league,  or  three  times  our  geographical  mile  of  60 
to  a  degree,  or  2025  yards,  is  6075  yards.  The  Brabant  league  is 
6096  yards.  The  Danish  and  Hamburg  league  is  8244  yards ; 
the  German  league  is  8101  yards;  the  long  German  league  is 
10126  yards ;  the  short  German  league  is  6859  yards ;  the  Portu- 
guese league  is  6760  yards ;  the  Spanish  league  is  7416  yards ; 
the  Swedish  league  is  11700  yards.  All  of  them  are  parts  of  a 
degree,  but  made  before  the  length  of  a  degree  was  accurately 
determined. 

Length  of  Days  in  DiflFerent  Countries. 

At  London,  England,  and  Bremen,  Prussia,  the  longest  day  has 
16i  hours.    At  Stockholm,  in  Sweden,  the  longest  day  has  18J 


THE   engineer's  HANDY-BOOK. 


383 


hours,  Hamburg  in  Germany,  and  Dantzic  in  Russia,  the 

longest  day  is  18  hours,  and  the  shortest  is  7.  At  St.  Petersburg 
in  Russia,  and  Tobolsk  in  Siberia,  the  longest  day  has  19  hours, 
and  the  shortest,  5L  At  Tornea,  in  Finland,  the  longest  day 
has  24  hours,  and  the  shortest  is  a  half-hour.  At  Wardbuys  in 
Norway,  the  longest  day  lasts  from  the  1st  of  May  to  the  22d  of 
July  without  interruption  ;  and  at  Spitzbergen  the  longest  day 
is  three  months  and  a  half.  At  New  York  the  longest  day  has 
15  hours  and  56  minutes;  and  at  Montreal  15^  hours. 


TABLE 


OF  SAILING  DISTANCES  FROM  NEW  YORK  TO  DIFFERENT  PARTS  OF  THE 
WORLD,  IN  GEOGRAPHICAL  MILES. 


To  Sandy  Hook  . 

18  miles. 

To  St.  Petersburg, 

4,420 

mile 

a 

Nantucket  Light 

.  211 

Havre  .    .  . 

3,148 

u 

n 

Boston    .    .  . 

302 

n 

(i 

San  Francisco, 

u 

Halifax  .    .  . 

666 

a 

via  Panama, 

5,249 

iC 

(( 

Cape  Henlopen . 

149 

u 

(( 

San  Francisco, 

(( 

Philadelphia  . 

252 

u 

via  Cape 

(< 

Cape  Henry 

276 

Horn .    .  . 

18,850 

u 

n 

Baltimore    .  . 

428 

Melbourne,  via 

n 

Washington 

434 

(( 

Cape  of  Good 

t( 

Norfolk  .    .  . 

306 

u 

Hope     .  . 

12,895 

n 

i( 

Richmond    .  . 

375 

(( 

u 

Nangasaki,  Ja- 

n 

Cape  Hatteras  . 

340 

pan   .    .  . 

9,800 

a 

a 

Charleston   .  . 

621 

n 

Sandwich  Isl- 

a 

Savannah     .  . 

716 

ands,  via 

u 

Key  West    .  . 

1,484 

Panama .  . 

7,157 

« 

Havana       .  . 

1,454 

u 

Canton,  via 

New  Orleans  . 

2,129 

Panama  . 

10,000 

u 

t( 

Vera  Cruz    .  . 

2,354 

Canton,  via 

(( 

Liverpool    .  . 

3,084 

Good  Hope, 

19,500 

« 

London       .  . 

3,225 

There  are  5280  feet  in  a  statute  mile. 


384         THE  engineer's  hanby-book. 


TABLE 

OF  LATITUDE  AND  LONGITUDE  OF  PLACES. 


Places. 

Latitude. 

Longitude. 



D.  M. 

D.  M. 

Quebec  

46  49  N. 

71  16  W. 

Halifax  ..... 

44  38  " 

63  65  " 

Portland  light  .... 

43  36  " 

70  12  " 

Buffalo  

42  53  " 

78  55  " 

Chicago  

42   0  " 

87  35  " 

Newburyport  light 

42  48  " 

70  49  " 

Boston  State-House 

42  21  " 

71    4  " 

Nantucket  light  .... 

41  23  " 

70    3  " 

Newport  ..... 

41  29  " 

71  19  " 

New  York  

40  42  " 

74   0  " 

Philadelphia  .... 

39  57  " 

75  10  " 

Cape  Heulopen  .... 

38  46  " 

75   4  " 

Cincinnati  ..... 

39    6  " 

84  27  " 

St.  Louis  ..... 

38  36  " 

89  36  " 

Richmond    .  . 

37  32  " 

77  27  "  ^ 

Washington  City  .... 

38  53  " 

77    3  "  3 

Baltimore     .       .       .  . 

39  18  " 

76  37  "  B 

Cape  Hatteras  .... 

35  14  " 

75  30  "  ? 

Charleston  light  .... 

32  42  " 

79  54  "  1 

Savannah   

32    5  " 

81    8  "  S 

Cape  Florida 

25  41  " 

80    5  "  g- 

Pensacola  

30  24  " 

87  10  "  ■ 

Mobile  

30  42  " 

87  69  " 

New  Orleans  .... 

29  57  " 

90   0  " 

San  Francisco  .... 

37  47  " 

122  21  " 

Cape  Horn  

55  59  " 

67  16  " 

Porto  Hico  

18  29  " 

66    7  " 

Cape  Hayti  

19  46  " 

72  11  " 

Havana  ..... 

23    9  " 

82  22  " 

Vera  Cruz  

19  12  " 

96    9  " 

Mexico  ..... 

19  26  " 

99    5  " 

Porto  Bello  .       .  . 

9  34  " 

79  40  " 

Cape  St.  Augustine 

8  21  S. 

34  57  " 

Rio  Janeiro  

22  56  " 

43    9  " 

[  Buenos  Ayres  .... 

34  36  " 

58  22  " 

THE    ENGI  NE  ER\s    HAN  I)  Y-  HOOK  . 


385 


TABLE  —  {Continued.) 

OF  LATITUDE  AND  LONGITUDE  OF  PLACES. 


Places. 

Latitude. 

Longitude.  | 

D. 

M. 

D. 

M. 

Cape  Horn   .       .       .       .  • 

Oo 

o. 

0  < 

1 

1  0 

w 

Valparaiso  ..... 

oo 

9 

ivr 
ii . 

71 

41 

London  ..... 

OL 

Ol 

(( 

A 

U 

0 

« 

Liverpool     .       .       .  . 

29 

9 

.^9 

OLi 

Greenwich  

9Q 

Dublin  ^      .       .       .       .  . 

53 

23 

it 

6 

20 

w. 

Paris  

^0 

0\} 

u 

9 
L 

90 

H. 

Marseilles     .       .  . 

43 

18 

5 

22 

i( 

Florence       .  . 

rlO 

4A 

(( 

1 1 

1 A 

1  0 

a 

Rome  ...... 

41 

54 

li 

12 

97 

<( 

Naples  

40 

^0 
o\j 

n 

1  4 
14 

16 

ID 

Berlin  

01 

a 

1  ^ 
10 

94 

Hamburg  

oo 

oo 

u 

Q 

•JO 

u  3 

Vienna  

lO 

1 

J  D 

9^ 

zo 

Constantinople  .... 

41 

1 

1 

a 

9^ 

OxJ 

a  2 

Stockholm  ..... 

Ou 

91 

ii 

1  9. 

10 

A 
4: 

Copenhagen  ..... 

OO 

41 

4:1 

a 

1  9 
1  z 

'^4 
04 

St.  Petersburg  .... 

59 

56 

n 

.^0 

19 

J.  €7 

Madrid  

40 

TtV/ 

9.^ 

i( 

Q 
O 

49 

vv 

Gibraltar      .       .       .  . 

ou 

o 

a 

90 

i< 

Lisbon  ...... 

38 

42 

a 

9 

9 

a 

Palermo  ..... 

38 

12 

15 

35 

(< 

Pekin  

39 

54 

ii 

116 

28 

E. 

Canton  ...... 

23 

7 

n 

113 

14 

Cape  of  Good  Hope 

34 

22 

S. 

IS 

30 

(< 

Sidney,  Australia  .... 

34 

0 

a 

151 

23 

(( 

Jerusalem  ..... 

31 

48 

N. 

37 

20 

(< 

TABLE 

SHOWING  THE  TIME  AT  DIFFERENT  PLACES  WHEN  IT  IS  12  O'CLOCK  NOON  AT  NEW  YORK. 


Washington,  D.  C.  . 
San  Francisco,  Cal. . 
Salt  Lake  City,  Utah 
Greenwich,  Eng. 
Liverpool,  " 
Paris,  France  . 

33 


Hours. 

Mill. 

11 

47 

48 

A.M. 

8 

46 

13 

it 

9 

27 

36 

« 

4 

56 

0 

P.M. 

4 

43 

59 

it 

5 

5 

21 

n 

386 


THE   engineer's  HANDY-BOOK. 


TABLE 

OF  MILES  AND  KNOTS,  KNOTS  AND  MILES. 

The  decimals  of  miles  in  this  table  are  repeaters,  and  when  four  is  used,  the  last 
figure  should  be  increased  by  one. 


Knots. 

Miles. 

Miles. 

Knots. 

1 

l-lol5 

1 

0-868421 

2 

2-3030 

2 

1-736842 

3 

3-4545 

3 

2-605263 

4 

4-6060* 

4 

3-473684  , 

5 

5-7575 

5 

4-342105 

6 

6-9090 

6 

5-210526 

7 

8-0606 

7 

6-078947 

8 

9-2121 

8 

6-947368 

9 

10-3636 

9 

7-815790 

10 

11-5151 

10 

8-684211 

11 

12-6666 

11 

9-552632 

12 

13-8181 

12 

10-421053 

13 

14-9696 

13 

11-289474 

14 

16-1212 

14 

12157895 

15 

17-2727 

15 

13-026316 

16 

18-4242 

16 

13-894737 

17 

19-5757 

17 

14-763158 

18 

20-7272 

18 

15-631579 

19 

21-8787 

19 

16-500000 

20 

23-0303 

20 

17-368420 

21 

24-1818 

21 

18-236841 

22 

25-3833 

22 

19-105262 

23 

26-4848 

23 

19-973683 

24 

27-6363 

24 

20-842104 

33 

38-0000 

38 

33-000000 

There  are  6080  feet  in  a  knot. 


Marine  Signals. 

While  it  must  be  admitted  that  we  have  made  great  improve- 
ment in  the  design  and  construction  not  only  of  the  hulls  of  steam- 
ships, but  also  of  the  machinery  and  all  other  appliances  con- 


THE   ENGINEEr\s  ITANDY-BOOK. 


387 


nected  with  their  use,  as  a  means  of  river,  lake,  and  ocean  naviga- 
tion, it  is  also  an  authenticated  fact,  that  the  number  of  marine 
disasters  increases,  especially  as  regards  steamships,  and  that  each 
succeeding  year  shows  an  increase  in  the  loss  of  steamships  as  well 
as  of  human  life  and  suffering.  While  light-houses  illuminate 
almost  every  coast,  yet  signals  of  distress  become  more  numer- 
ous and  more  dark,  until  the  surf,  as  it  were,  is  hoarse  with  the 
cries  of  drowning  men.  The  questions  may  naturally  be  asked, 
in  view  of  the  foregoing  facts,  Have  our  ship-builders  become 
more  unscrupulous?  the  weather  more  changeable?  or  the  sea 
more  dangerous  ?  Within  the  last  thirty-seven  years,  fifty-six  large 
ocean  steamers  have  been  wrecked,  involving  a  loss  of  4780  lives  and 
over  forty  millions  of  dollars^  worth  of  property,  and  out  of  the  whole 
number  only  tivo  were  lost  from  accidents  to  machinery. 

There  are  three  classes  of  marine  signals  in  use  as  a  means  of 
warning  the  mariner  of  his  proximity  to  danger,  viz.,  day  signals, 
night  signals,  and  fog  signals.  They  address  themselves  to  the 
eye  and  to  the  ear.  Day  signals,  as  a  rule,  are  made  with  flags, 
as  these  furnish  the  simplest  and  probably  the  best  medium  of 
communication,  whenever  objects  can  be  made  out,  and  vessels 
are  beyond  hailing  distance.  Besides  the  light-house,  there  are 
three  kinds  of  night  signals  used  which  produce  sound,  viz.,  the 
syren,  the  whistle,  and  the  bell.  The  light-house,  like  the  flag, 
is  undoubtedly  the  most  reliable  and  precise  when  the  air  is 
clear ;  but  it  frequently  unfortunately  happens  that  the  strongest 
lights,  even  the  most  powerful  electric  lights,  are  often  obscured 
and  rendered  invisible  by  fog.  As  a  result,  during  heavy  fogs  by 
day  or  night,  recourse  must  be  had  to  instruments  which  produce 
sound,  such  as  the  syren,  the  whistle,  and  the  bell. 

The  theory  with  regard  to  their  use  is,  that  they  are  capable  of 
emitting  sounds  of  such  intensity  as  to  be  heard  at  a  distance  suf. 
ficient  to  avert  impending  danger,  providing  that  the  oflScer  of  the 
watch  is  sufficiently  wide  awake  to  hear  them.  It  frequently  happens 
that  the  first  indication  that  the  mariner  has  of  his  approach  to 
danger  is  a  dull,  muffled  sound  rising  slightly  above  the  roar  of 


S88 


THE   ENGINEER'S  HANDY-BOOK. 


the  surf,  the  noise  on  board,  or  the  wash  of  the  water.  He  may 
be  undecided  as  to  the  character  of  the  sound,  or  from  whence  it 
arose,  and,  before  giving  orders,  listens  for  its  repetition,  but  dur- 
ing all  this  time  the  ship  is  rushing  on  to  danger,  or  perhaps  to 
destruction.  Even  if  he  should  fully  comprehend  the  nature  of 
the  sound  and  give  orders,  they  may  not  be  fully  and  quickly 
comprehended ;  the  steamer  may  be  sluggish  in  her  movements, 
the  engineer  may  not  be  at  his  post  or  close  to  the  gear,  or  he  may 
be  drowsy  and  not  fully  understand  the  bells.  Any  of  the  fore- 
going circumstances  may  arise,  and,  though  trivial  in  themselves 
under  ordinary  conditions,  are  of  vital  importance  when  a  steam- 
ship, freighted  with  numerous  lives  and  a  valuable  cargo,  is  rush- 
ing on  to  danger.  Under  such  circumstances,  courage,  self-posses- 
sion, and  that  spontaneous  knowledge  of  what  to  do  in  moments  of 
extreme  peril,  are  invaluable  qualifications  in  the  officer  in  charge. 

A  steamship  from  three  to  four  hundred  feet  in  length,  that 
steers  well  under  full  steam  or  sail,  must  receive  a  warning  signal 
at  least  two  miles  from  it  in  distance,  as  it  will  require  a  circle 
of  at  least  5000  feet,  or  y%  of  a  mile,  in  which^  to  turn  such  a 
vessel  in  smooth  water;  and  it  will  take  from  ten  to  fifteen  minutes 
to  head  her  course  directly  opposite  to  the  one  in  which  she  was 
steering  when  the  signal  was  given,  when  she  will  be  found  to  be 
nearly,  if  not  quite,  a  mile  from  the  line  in  which  she  was  sailing 
when  the  helm  was  put  hard  over.  It  will  take  from  seven  to  ten 
minutes  to  head  her  course  in  a  direction  at  right  angles  to  the 
one  in  which  she  was  steering.  In  so  doing  she  will  describe  a 
semicircle  of  at  least  half  a  mile,  and,  under  the  most  favorable 
circumstances  of  wind  and  sea,  it  will  take  from  five  to  ten  minutes 
to  head  her  square  from  danger.  If  all  the  surroundings  were 
known,  the  same  vessel  might  be  stopped,  backed,  and  be  capable 
of  reversing  her  motion  in  a  period  of  five  minutes.  But  it  must 
be  understood  that  the  foregoing  evolutions  must  be  performed 
under  the  most  favorable  circumstances  of  sea,  wind,  weather,  and 
sound,  which  goes  to  show  that  a  signal  to  be  efficient  must  be 
adapted  to  each  and  every  one  of  the  foregoing  cases. 


THE   ENGINEER'S  HANDY-BOOK. 


389 


A  proper  system  of  lights  and  signals  is  of  great  importance,  as 
they  enable  the  mariner  to  shorten  his  voyage,  and  thus  to  facili- 
tate travel  and  cheapen  freights.  But  what  is  needed  is  a  system 
by  which  the  signals  might  be  placed  by  the  side  of  the  ordinary 
track  of  vessels,  indicating  to  the  mariner  that  he  is  right  and  in 
a  position  of  safety.  Vessels  might  approach  such  stations  in 
safety,  observe  their  number,  and  take  a  new  departure  from  each, 
the  result  of  which  would  be  that  the  most  dangerous  highways 
of  the  sea,  and  the  most  intricate  channels,  might  be  navigated  in 
the  most  foggy  weather. 


Marine  Whistle-Signals. 

When  two  steamships  or  boats  are  approaching  each  other 
from  opposite  directions,  one  puff  of  the  whistle  means  keep  to  the 

right,  thuSy  ^^^^J^^^^  >  which  will  bring  the  port,  or  red,  light 

of  each  vessel  in  full  view  of  the  other. 

When  two  steamers  are  approaching  each  other  from  opposite  di- 
rections, two  puffs  of  the  whistle  mean  go  to  the  left,  thus,/^ 

which  will  bring  the  green,  or  starboard,  lights  opposite  each 
other. 

When  two  steamboats  are  moving  in  the  same  direction,  one 
behind  the  other,  and  the  hindermost  one  wishes  to  pass  the  steam- 
boat ahead,  if  one  puff  of  the  whistle  is  given,  she  passes  ahead  on  the 


right  side,  thus,  ,  showing  the  red,  or  port,  light  of 


the  passing  boat  and  the  green,  or  starboard,  light  of  the  boat 
being  passed.  Under  the  same  circumstances,  if  two  puffs  of  the 
whistle  are  given,  it  means  that  the  hindermost  boat  is  coming  up 
on  the  left  side,  in  which  case  the  passing  boat  shows  the  star- 
board, or  green,  light,  while  the  boat  being  passed  shows  the  port, 
or  red,  light. 

Three  puffs  of  the  whistle  is  a  salute,  and  four  or  more  a  call 

33* 


390 


THE   engineer's  HANDY-BOOK. 


for  an  approachiDg  steamer  to  slow  down,  stop,  or  come  alongside, 
as  the  case  may  be. 

One  long  puff  of  the  whistle  is  usually  given  when  backing  out 
of  the  dock,  and  one  short  puff  is  a  call  to  the  deck  hand. 

Marine  Bell-Signals. 

Steamboat  bell-sign<als  for  engineers  in  the  mercantile  service 
are  as  follows : 

When  the  engine  is  at  rest,  on  receiving  one  hell,  the  engineer 
starts  ahead  slowly,  and  continues  until  he  receives  a  jingle-bell, 
which  is  a  signal  to  steam  at  full  speed. 

When  running  at  full  speed,  one  bell  means  to  slow  down,  after 
which  one  bell  signifies  to  stop.  Under  the  same  circumstances, 
two  bells  in  succession  signify  stop,  four  bells  in  succession  signify 
reverse  and  move  backward  at  full  speed. 

When  the  engine  is  at  rest,  two  bells  signify  to  go  backward  at 
full  speed.  If  it  is  desired  to  go  slowly  backward,  the  orders  are 
generally  sent  down  through  the  speaking-tube,  or  communicated 
to  the  engineer  by  light  or  heavy  taps  on  the  gong. 

Light  Signals  for  Ocean  Steamships. 

When  under  way,  a  bright  white  light  is  fixed  on  the  foremast, 
so  as  to  show  the  light  ten  points  on  each  side  of  the  ship,  a 
green  light  on  the  starboard  side,  and  a  red  light  on  the  port  side, 
so  constructed  as  to  show  the  same  number  of  points. 

Coasting  steamers  navigating  the  bays,  lakes,  rivers,  or  inland 
waters  of  the  United  States  shall  carry  a  bright  light  at  the  gaff*- 
end  or  flag-staff*,  in  addition  to  the  side-lights. 

Steam-tugs,  when  towing,  must  carry  two  bright  mast-head 
lights  vertically  (one  above  the  other),  in  addition  to  their  side- 
lights, so  as  to  distinguish  them  from  other  steamships. 

Fog-signals. —  Steamships,  when  under  way,  must  use  a  steam- 
whistle  at  intervals  of  not  more  than  one  minute.  Sailing-ships, 
when  under  way,  must  use  a  fog-horn  every  five  minutes. 


THE   engineer's  HANDY-BOOK. 


391 


Precautions.— In  case  of  two  steamships  meeting,  in  order  to 
avoid  the  risk  of  collision,  the  helms  of  both  should  be  put  to 
port,  so  that  each  may  pass  on  the  port  side  of  the  other. 

Signals  of  distress. —  By  day,  the  firing  of  a  gun  at  intervals 
of  about  a  minute,  or  the  distant  signal,  consisting  of  a  square 
flag,  having  a  ball  above  or  a  ball  below,  and  by  night  a  gun, 
rocket,  or  shell  fired  at  intervals  of  about  a  minute,  or  flames  on 
the  ship  (as  from  burning  a  tar-barrel),  etc. 

Distant  signals.  — B,  Ask  name  of  ship  or  signal  station  in 
sight ;  C,  Yes ;  D,  No ;  F,  Repeat  signal  —  make  it  more  conspic- 
uous ;  G,  Come  nearer. 

Railroad  Signals. 

Red  signifies  danger,  and  is  a  signal  to  stop. 
Green  signifies  caution,  and  is  a  signal  to  go  slotvly,  ^ 
White  signifies  safety,  and  is  a  signal  to  go  on. 
Green  and  white  is  a  signal  to  be  used  to  stop  trains  at  flag- 
stations. 

Blue  is  a  signal  to  be  used  by  car-inspectors. 
Flags  of  the  proper  color  must  be  used  by  day,  and  lamps  of 
the  proper  color  at  night  or  in  foggy  weather. 

Red  flags  or  red  lanterns  must  never  be  used  as  caution-signals; 
they  always  signify  danger.  Stop. 

A  lantern  swung  across  the  track,  a  flag,  hat,  or  any  object 
waved  violently  by  any  person  on  the  track,  signifies  danger ,  and 
is  a  signal  to  stop. 

An  exploding-cap  or  torpedo  clamped  to  the  top  of  the  rail  is 
an  extra  danger-signaly  to  be  used,  in  addition  to  the  regular  signals 
at  night,  in  foggy  weather,  and  in  cases  of  accident  or  emergency, 
:  when  other  signals  cannot  be  distinctly  seen  or  relied  on. 
!     The  explosion  of  one  of  these  signals  is  a  warning  to  stop  the 
I  train  immediately ;  the  explosion  of  two  is  a  warning  to  check 
\  the  speed  of  the  train  immediately,  and  look  out  for  the  regular 
danger-signal. 

A  fusee  is  an  extra  caution-signal,  to  be  lighted  and  thrown  on 


392 


THE    ENGINEER'S  HANDY-BOOK. 


the  track  at  frequent  intervals  by  the  flagman  of  passenger-trains 
at  night  whenever  the  train  is  not  making  schedule  time  between 
telegraph-stations. 

A  train  finding  a  fusee  burning  upon  the  track  must  come  to  a 
full  stop,  and  not  proceed  until  it  is  burned  out. 

Train  Signals. 

Each  train,  or  engine  without  a  train,  while  running  after  sun- 
set, or  during  the  day  in  foggy  weather,  must  display  the  white 
headlight  in  front  of  the  engine,  and  two  red  lights  in  the  rear  of 
the  train  or  engine,  except  shifting-engines  in  yards,  which  will 
display  two  green  lights  instead  of  red. 

Each  passenger-train  while  running  must  have  a  bell-cord  at- 
tached to  the  signal-bell  of  the  engine,  passing  over  or  through  the 
entire  length,  and  secured  to  the  rear  end  of  the  train. 

Each  passenger-train  while  running  must  display  one  green  flag 
at  the  rear  by  day,  and  two  green  lights,  one  at  each  side  of  the 
rear  car,  at  night,  as  markers,  to  enable  operators  and  enginemen 
to  know  that  the  whole  of  the  train  is  attached  to  the  engine. 

Each  freight-train  while  running  must  display  two  green  flags 
by  day,  and  two  green  lights  at  night,  one  on  each  side  of  the  rear 
car,  as  markers,  to  enable  operators  and  trainmen  to  know  that 
the  whole  of  the  train  is  attached  to  the  engine. 

Two  green  flags  by  day,  and  two  green  lights  at  night,  carried 
in  front  of  an  engine,  denote  that  the  engine  or  train  is  followed 
by  another  engine  or  train  running  on  the  same  schedule.  The 
engine  or  train  thus  signalled  will  be  entitled  to  the  same  schedule 
rights  and  privileges  as  the  engine  or  train  carrying  the  signals. 

Two  white  flags  by  day,  and  two  white  lights  at  night,  carried 
in  front  of  an  engine,  denote  that  the  engine  or  train  is  extra. 
These  signals  shall  always  be  displayed  by  all  work  and  extra 
trains  or  engines,  except  when  running  as  a  regular  train. 

A  blue  flag  by  day,  and  a  blue  light  by  night,  placed  in  the  draw- 
head  or  on  the  platform  or  step  of  a  car,  at  the  end  of  a  car  stand- 


THE   ENGINEER'S   HANDY-BOOK.  393 

ing  on  the  main  track  or  sidings,  denote  that  car  repairmen  are 
at  work  underneath  the  cars.  The  car  or  train  thus  protected 
shall  not  be  coupled  to,  or  move  until  the  blue  signal  is  removed 
by  the  car  repairmen. 

Enginemen's  Signals. 

One  short  blast  of  the  whistle  is  a  signal  to  apply  the  brakes 
—  Stop.    Thus,  — . 

Two  long  blasts  of  the  whistle  is  a  signal  to  throw  off  the  brakes. 
Thus,  . 

Two  short  blasts  of  the  whistle  when  running  is  an  answer  to 
signal  of  conductor  to  stop  at  next  station.    Thus,  . 

Three  short  blasts  of  the  whistle  when  standing  is  a  signal  that 
the  engine  or  train  will  back.    Thus,  . 

Three  short  blasts  of  the  whistle  when  running  is  a  signal  to 
be  given  by  passenger-trains,  when  carrying  signals  for  a  follow- 
ing train,  to  call  the  attention  of  trains  they  pass  to  the  signals. 
Thus,  — . 

Four  long  blasts  of  the  whistle  is  a  signal  to  call  in  the  flagman 
or  signalman.    37ms,  . 

Four  short  blasts  of  the  whistle  is  the  engineman's  call  for  sig- 
nals.   Thus,  . 

Two  long  followed  by  two  short  blasts  of  the  whistle  when 
running  is  the  signal  for  approaching  a  road  crossing  at  grade. 
Thus,  . 

Five  short  blasts  of  the  whistle  is  a  signal  to  the  flagman  to  go 
back  and  protect  the  rear  of  the  train.    Thus,  . 

A  succession  of  short  blasts  of  the  whistle  is  an  alarm  for  cattle, 
and  calls  the  attention  of  trainmen  to  danger  ahead. 

A  blast  of  the  whistle  of  five  seconds'  duration  is  a  signal  for 
approaching  stations,  railroad  crossings,  and  draw-bridges. 


394  THE  engineer's  handy-book. 


Conductors'  Signals. 

BY  BELL-CORD. 

One  tap  of  the  signal-bell  when  the  engine  is  standing  is  a  notice 
to  start. 

Two  taps  of  the  signal-bell  when  the  engine  is  standing  is  a  notice 
to  call  in  the  flagman. 

Two  taps  of  the  signal-bell  when  the  engine  is  running  is  a 
notice  to  stop  at  once. 

Three  taps  of  the  signal-bell  when  the  engine  is  standing  is  a 
notice  to  back  the  train. 

Three  taps  of  the  signal-bell  when  the  engine  is  running  is  a 
signal  to  stop  at  the  next  station. 

Signals  by  Lamp. 

A  lamp  swung  across  the  track  is  a  signal  to  stop. 

A  lamp  raised  and  lowered  vertically  is  a  signal  to  move  ahead. 

A  lamp  swung  in  a  circle  is  a  signal  to  move  back. 

The  Screw- Propeller. 

The  screw-propeller,  so  commonly  applied  to  the  propulsion 
of  vessels,  consists  of  two,  three,  or  four  helical  or  twisted  blades 
set  upon  a  shaft,  or  axis,  revolving  beneath  the  water  at  the  stern. 
Experience  has  shown  that  no  screw-propeller,  designed  or  in- 
vented up  to  the  present  time,  has  proved  superior  to  all  others 
for  all  ships.  The  best  propeller  for  any  vessel  is  the  one  best 
suited  for  that  model,  regardless  of  the  number  of  blades,  diameter, 
or  pitch.  •  The  principles  of  screw-propulsion  embrace  those  re- 
lating to  hydraulics  also,  so  that,  in  proportioning  the  screw,  the 
lines  of  the  hull  should  be  considered. 

The  pitch  of  the  screw  is  the  distance  that  it  would  advance  in 
one  revolution,  if  working  in  a  solid,  fixed  nut ;  or  it  is  the  dis- 
tance between  the  threads  measured  in  a  line  with  the  shaft.  The 


THE   ENGINEER'S  HANDY-BOOK. 


395 


pitch  of  a  screw,  or  the  circumference  of  a  paddle-wheel,  multi- 
plied by  the  revolutions,  and  two  figures  cut  off  for  decimals,  gives 
the  speed  in  knots  per  hour. 

The  term  left-handed  propeller  means  a  screw  with  a  left-handed 
thread,  and  a  right-handed  one  has  a  right-handed  thread.  A  left- 
handed  propeller,  to  move  the  ship  ahead,  goes  from  left  to  right, 
while  a  right-handed  one  turns  from  right  to  left,  looking  from 
the  engine-room  towards  the  stern  of  the  boat. 

The  force  which  drives  a  vessel  forward  when  a  screw-propeller 
is  used,  is  the  pressure  exerted  against  the  thrust-block.  Steam 
being  admitted  to  the  cylinder,  causes  the  piston  to  move,  and 
the  motion  being  transmitted  through  the  connecting-rod  to  the 
crank-pin,  crank,  and  propeller  shafts,  causes  the  latter  to  revolve, 
by  which  the  pressure  it  exerts  against  the  water  is  transmitted  to 
the  thrust-block,  and  the  vessel  forced  forward. 

The  term  slip  of  the  screw  "  means  the  difference  between 
the  actual  advance  of  the  propeller  through  the  water,  and  the 
advance  which  would  be  accomplished,  if  there  was  no  recession 
of  the  water  produced  by  the  pressure  of  the  propelling  surface. 
A  screw  of  15  feet,  if  working  in  a  stationary  nut,  would  advance 
15  feet  for  every  revolution  ;  but  when  it  acts  in  the  water,  it  may 
only  advance  14  feet  or  less,  the  difference  being  caused  by  the 
water  being  pressed  back,  owing  to  its  inertia  being  inadequate  to 
resist  the  moving  force.  In  such  cases  the  slip  is  said  to  be  1  foot 
in  15,  or  nearly  7  per  cent.  loss. 

Measurement  of  the  screw-propeller. — The  surface  of  a  screw- 
propeller  is  the  same  as  would  be  generated  by  a  line  revolving 
around  a  cylinder,  through  the  axis  of  which  it  passes,*and  at  the 
same  time  advancing  along  the  axis.  To  find  the  area  of  a  pro- 
peller-shaft, square  the  diameter,  and  multiply  by  the  decimal, 
•7854. 

The  Errickson  and  Delameter  propellers  are  those  most  gen- 
erally used,  although  the  Loper  Screw,  as  it  is  termed,  is  frequently 
employed,  but  it  has  now  nearly  gone  out  of  use. 

The  thrust- block  of  a  propeller  is  formed  of  a  series  of  rings, 


396 


THE   ENGINEER'S  HANDY-BOOK, 


generally  of  brass,  with  spaces  between  them,  into  which  an  equal 
number  of  solid  collars  fit.  The  thrust  is  exerted  against  the  fore 
and  aft  faces  of  these  rings  and  collars. 

The  stern -tube  is  a  tunnel  located  in  the  dead  wood  of  a  ship,  in 
which  the  propeller-shaft  revolves.  Its  outer  end  is  made  water-tight 
by  a  stuflSng-box  containing  a  fibrous  packing.  Stern-tubes  were  for- 
merly made  of  wood,  but  they  are  now  generally  made  of  boiler-plate. 

The  Paddle-wheel. 

The  advantages  of  the  paddle-wheel  as  a  motive-power  de- 
pend on  the  amount'  of  the  immersion.  When  the  water  ap- 
proaches the  centre  or  reaches  above  it,  it  is  obvious  that  great 
waste  of  power  will  ensue.  It  is  quite  as  obvious  that  the 
greater  the  diameter  of  the  wheel  the  greater  the  leverage,  and 
the  greater  is  the  effect  obtained. 

The  slip  of  the  paddle  is  caused  by  the  recession  of  the  water 
from  the  buckets,  or  it  is  a  retrograde  motion  given  to  the  water 
in  a  line  parallel  to  the  direction  in  which  the  ship  is  moving. 
The  slip  of  the  wheel  is  the  diflference  between  the  speed  of  the 
ship  and  that  of  the  wheel.  The  amount  of  slip  is  determined 
by  finding  the  speed  of  the  ship  in  feet  per  hour  and  subtracting 
it  from  the  speed  of  the  wheel  at  the  centre  of  pressure,  or  centre 
of  action,  in  feet  per  hour. 

The  centre  of  action  is  that  point  in  a  wheel  in  which  the  effect 
would  not  be  altered  if  the  whole  action  of  the  water  were  con- 
centrated. The  centre  of  action  may  be  thus  determined :  Lay 
down  the  wheel  to  a  certain  scale  and  line  off*  the  dip  on  it. 
Take  -|  of  the  breadth  of  the  totally-immersed  paddles  and  |  of 
the  depth  of  those  partially  immersed,  and  add  them ;  their  sum 
divided  by  the  number  of  paddles  partially  or  totally  in  the 
water  will  give  the  distance  of  the  centre  of  action  from  the  edge 
of  the  floats.  This  distance  subtracted  from  the  radius  of  the 
wheel,  and  multiplied  by  2,  will  give  the  diameter  of  the  centre 
of  action  of  the  wheel.  The  dip  of  the  wheel  is  69  inches,  and, 
at  that  dip,  there  are  7  full-immersed  floats  and  one  immersed 


THE    ENGINEEr\s    H  A  N  D  Y  -  H  O  O  K  . 


397 


15  inches,  making  8  floats ;  depth  of  bucket,  21  inches.  Find  the 
speed  of  the  circumference  at  the  centre  of  action  in  the  paddles 
in  feet  per  hour;  diameter  of  wheel,  36  feet;  revolutions,  15  per 
minute.  First  take  centre  of  action  at  |  the  mean  depth  of  the 
immersed  paddles,  then  |  of  21  =  7,  which,  multiplied  by  7,  = 
49  ;  ^  of  15  =  5  ;  5x1=5;  49  +  5  =  54,  which  divided  by  8, 
the  number  of  buckets,  =  6*75,  which  is  the  distance  of  the  centre 
of  action  from  the  outer  edge  of  the  floats.  Then  6*75  x  2  = 
13-5  inches ;  36  feet  =  432  inches ;  and  432  — 13*5  =  418*5  -r- 12 
=  34*883,  which  is  the  diameter  of  the  centre  of  action  of  the 
paddles,  and  this  X  3*1416  =  109*5884,  which  is  the  circumference 
of  their  centre  of  action.  Then  109*5884  feet  x  15  revolutions 
X  60  minutes  in  an  hour  =  98,629  ft.,  the  speed  of  circumference 
at  the  centre  of  action  of  the  paddles  in  feet-power  as  required. 

The  speed  of  the  ship  being  12i  miles  per  hour,  the  percentage 
of  slip  of  the  above  wheel  may  be  calculated  thus :  6082*66  ft.  is 
a  nautical  mile,  which  multiplied  by  12}  =  74,512*58  =  speed  of 
ship  in  feet  per  hour.  Then  the  speed  of  the  centre  of  circum- 
ference of  action  in  feet  per  hour  is  98,629  —  74,512*58  speed  of 
ship  =  24,116*42,  slip  of  centre  of  action  of  paddles  in  feet  per 
hour.  The  percentage  of  slip  would  then  be  98,629  :  24,116*42 
: :  100  :  24*44,  which  is  the  percentage  of  slip. 

Loss  from  oblique  action  is  the  loss  in  the  common  radial  wheel 
occasioned  by  the  floats  striking  the  water  at  an  angle.  Oblique 
action  consists  of  a  vertical  depression  and  lifting  of  the  water  by 
the  entering  and  emerging  floats.  This  loss  is  calculated  by  the 
square  of  the  sines  of  the  angles  at  which  the  buckets  strike  or 
enter  the  water.  This  may  be  explained  as  follows :  When  a  body 
strikes  obliquely  on  a  plane,  the  force  of  impact  with  any  given 
velocity  varies  according  to  the  sines  of  the  angle  of  incidence, 
and  therefore  the  force  with  which  the  particles  of  water  strike 
against  a  board  will  vary  according  to  the  sines  of  the  angles  at 
which  they  strike.  This  force  is  gradually  growing  less  as  the 
board  is  turned  on  its  edge.  The  number  of  particles  striking 
the  board  also  vary  according  to  the  sines  of  the  angles  of  inci- 
34 


398 


THE   ENGINEER'S  HANDY-BOOK. 


dence,  or,  in  other  words,  according  to  the  perpendicular  height 
of  the  inclined  board ;  so  that  the  resistance,  as  it  varies  both  with 
the  force  with  which  the  particles  strike  the  board  and  the  number 
of  particles  which  strike  it,  must  vary  according  to  the  squares 
of  the  sines  of  the  angle  of  incidence.  This  loss  from  oblique 
action  may  be  obviated  by  using  the  feathering  wheel,  in  which 
each  float  is  hung  upon  a  centre,  and  so  arranged,  by  a  suitable 
mechanism,  as  to  be  always  in  a  vertical  position. 

The  rolling -circle  of  a  wheel  is  a  circle  whose  circumference 
multiplied  by  the  number  of  revolutions  of  the  wheel  in  a  given 
time  equals  the  speed  of  the  vessel  in  the  same  time ;  or  it  is  a  circle 
at  any  point  in  the  circumference,  which  moves  with  the  same  ve- 
locity as  the  speed  of  the  ship.  The  diameter  of  the  rolling-circle 
of  a  wheel  is  found  as  follows:  Divide  the  speed  of  the  ship  in 
feet  per  hour  by  the  number  of  revolutions  per  hour;  the  quotient 
will  be  the  circumference  of  the  rolling-circle;  10  X  5*280  = 
52*800  -T-  600  (number  of  revolutions  per  hour)  =  '88,  the  circum- 
ference of  the  rolling-circle;  and '88  H- 3*1416  =  28*01, the  diameter 
of  a  rolling-circle.  A  disconnecting-paddle  engine  is  one  in  which 
the  paddle-wheel  can  be  thrown  out  of  gear  by  sliding  back  a  clutch 
on  the  main-shaft.  The  crank-pin  is  made  fast  in  the  outer  shaft, 
and,  if  desired  to  stop  one  engine,  the  throttle  is  shut,  and  the 
clutch  on  the  shaft  slipped  back,  which  enables  either  engine  to 
be  reversed  or  stopped  independently  of  the  other. 

The  names  of  the  different  paddle-wheels  are  the  cycloidal,  the 
manly,  the  radial,  and  the  feathering.  The  two  former,  though  pos- 
sessing some  good  features,  for  certain  reasons  have  never  come  into 
very  general  use,  while  the  latter  are  almost  universally  adopted.  The 
feathering  wheel  is  capable  of  producing  more  useful  effect  with  less 
power  than  the  radial  wheel,  but  it  has  the  disadvantages  of  great 
weight,  extra  first  cost,  as  well  as  great  expense  of  maintenance. 

The  usual  rule  for  calculating  the  horse-power  of  an  engine 
cannot  be  applied  to  calculate  the  actual  horse-power  available 
for  propelling  a  vessel,  as  much  of  this  power  is  lost  by  the  slip 
of  the  wheel  and  the  oblique  action  of  the  buckets. 


THE   engineer's  HANDY-ROOK. 


399 


Comparative  efficiency  0/  the  screw-propeller  and  paddle-wheel, — 
When  a  vessel  is  propelled  through  the  water,  she  necessarily  puts 
a  column  of  water  into  motion  in  the  direction  of  her  advance. 
In  the  case  of  paddle-wheels,  none  of  the  power  expended  in  pro- 
ducing the  current  is  recovered ;  but  with  the  screw  the  case  is 
different,  as  the  effect  of  the  current  reduces  the  number  of  rota- 
tions requisite  for  the  production  of  any  prescribed  speed.  In 
short  vessels,  in  consequence  of  the  rubbing  surface  of  the  bottom 
not  being  sufficient  to  generate  a  current,  there  is  little  difference 
between  the  performances  of  the  paddle  and  screw ;  but  in  long 
vessels,  where  the  water  is  more  effectually  rubbed  into  motion, 
the  superior  efficiency  of  the  screw  over  any  species  of  side  pro- 
peller becomes  very  conspicuous. 

In  the  early  trials  between  paddle-  and  screw-vessels,  the  two 
instruments  appeared  to  be  of  about  equal  efficiency.  This  com- 
parison was  made  between  the  screw  and  radial  paddle.  But  wuth 
the  feathering  paddle  the  efficiency  is  found  to  be  greater  in  con- 
sequence of  the  floats  entering  and  leaving  the  water  edgewise. 
Feathering  wheels  have  the  further  advantage  for  river  navigation^ 
that,  as  the  diameter  of  the  wheel  may  be  reduced  without  giving 
rise  to  other  difficulties,  the  speed  of  the  engine  may  be  increased. 

In  vessels  of  moderate  dimensions,  the  screw  is  found  to  be  of 
about  equal  efficiency  to  the  radial  paddle,  and  of  somewhat  infe- 
rior efficacy  to  the  feathering  paddle ;  but  in  vessels  of  large  size, 
the  screw  is  found  to  be  of  considerably  greater  efficacy  than  pad- 
dles .of  any  kind. 

Relation  between  the  power  and  speed  of  steam-vessels,  —  When 
the  relation  between  the  pitch  of  the  screw  and  the  speed  of  the 
vessel  is  considered,  and  also  that  the  pitch  must  be  determined 
and  the  screw  made  before  the  vessel  is  tried,  it  must  be  obvious 
how  important  it  is  that  marine  engineers  should  clearly  under- 
stand the  laws  affecting  the  motion  of  solid  bodies  in  fluids.  A 
few  words  will  not,  therefore,  be  out  of  place  on  this  important  sub- 
ject. When  a  steamboat  makes  a  voyage  between  port  and  port, 
she  in  effect  excavates  a  canal  between  those  ports,  the  transverse 


400 


THE   ENGINEER'S  HANDY-BOOK. 


section  of  which  corresponds  with  the  immersed  midship  section 
of  the  vessel.  It  is  true  this  canal  is  immediately  filled  up  again, 
but  yet  this  canal  is  really  cut,  and  the  work  of  the  engine  is  ex- 
pended in  cutting  it.  After  uniform  motion  has  been  attained  by 
the  vessel,  the  work  of  the  engine  is  transferred  to  the  water  pushed 
out  of  the  canal.  Now,  for  similar  speeds,  the  work  per  mile,  or 
per  hour,  must  be  as  the  immersed  midship  section  of  the  vessel. 

Effect  of  size  on  the  speed  of  steam-vessels. — All  experiments 
confirm  the  theory,  that  to  give  one  body  twice  the  velocity  of  an- 
other, it  will  necessarily  require  the  expenditure  of  four  times  the 
amount  of  energy.  Assuming  that  fluid  bodies  follow,  with  re- 
spect to  motion,  the  same  laws  as  solids ;  if  two  vessels  are  making 
voyages,  having  the  same  immersed  midship  section,  they  will  dis- 
place similar  quantities  of  water  from  their  course,  regardless  of 
speed.  The  water  having  motion  given  to  it,  the  power  ex- 
pended will  be  in  proportion  to  the  square  of  the  velocity  given 
to  it. 

To  find  the  mean  speed  of  a  steam-vessel. —  The  mean  speed  of  a 
steam-vessel,  from  a  number  of  runs  over  a  measured  knot  where 
the  tidal  influence  is  always  varying,  may  be  ascertained  as  fol- 
lows :  Add  the  different  speeds  for  the  trials,  and  divide  by  the 
number  of  trials.    This  will  give  the  approximate  mean  speed. 

The  great  difficulty  with  paddle-wheels  is  to  secure  a  proper 
immersion.  As  the  ship  proceeds  on  its  voyage,  and  consumes 
its  store  of  coal,  the  vessel  becomes  lighter,  and  consequently  its 
draught  of  water  decreases.  Therefore,  supposing  a  paddk  is 
properly  immersed  at  the  commencement  of  a  voyage,  it  will  be 
partially  out  of  the  water  at  the  end.  At  the  commencement  of 
a  voyage,  the  paddle  must  be  too  deeply  immersed,  so  that  at  the 
middle  the  proper  immersion  may  be  attained,  while  there  will 
be  too  little  towards  the  end  of  the  voyage.  The  paddle-wheel 
is  fast  giving  place  to  the  screw-propeller,  for  the  reason  that  it 
offers  greater  resistance  to  the  v^'md  in  case  of  storm,  thus  inducing 
oscillation  of  the  vessel,  besides  being  more  exposed  to  the  shots 
of  an  enemy  in  time  of  war. 


THE   ENGINEER\s  HANDY-BOOK. 


401 


Pumps. 

Pumps,  of  whatever  design  or  construction,  or  for  whatever  pur- 
pose employed,  are  simply  hydraulic  machines  attached  to  one 
end  of  a  tube,  for  the  purpose  of  raising, 
forcing,  or  transferring  water,  or  other 
liquids  or  fluids.  The  idea  entertained 
by  many  that  water  is  raised  by  suction 
is  erroneous,  as,  properly  speaking,  there 
is  no  such  principle  as  suction.  Atmos- 
pheric "  lift  "  or  "  suction  pumps  cause 
the  water  to  raise  itself  by  having  its 
surface  relieved  of  the  column  of  air 
resting  upon  it.  If,  therefore,  one  end  of  a  pipe  or  tube  be  lowered 
into  water,  the  other  end  be  closed  by  means  of  a  valve  or  other 
device,  and  the  air  contained  in  the  pipe  be  drawn  out,  it  is  evi- 
dent that  the  surface  of  the  water  within  the  pipe  will  be  relieved 
of  the  pressure  of  the  atmosphere.  There  will  then  be  no  resist- 
ance offered  to  the  water  to  prevent  its  rising  in  the  tube.  The 
water  outside  of  the  pipe,  still  having  the  pressure  of  the  atmos- 
phere upon  its  surface,  therefore  forces  water  up  into  the  pipe,  sup- 
plying the  place  of  the  excluded  air,  while  the  water  inside  the 
pipe  will  rise  above  the  level  of  that  outside  of  it,  proportionally 
to  the  extent  to  which  it  is  relieved  of  the  pressure  of  the  air ;  so 
that,  if  the  first  stroke  of  a  pump  reduce  the  pressure  of  the  air 
contained  in  the  pipe  from  15  pounds  per  square  inch  (which  is  its 
normal  pressure)  to  14  pounds,  the  water  will  be  forced  up  the  pipe 
to  the  distance  of  about  2i  feet,  since  a  column  of  water  an  inch 
square,  and  2}  feet  high,  is  equal  to  about  one  pound  in  weight. 

It  is  evident  that,  upon  the  reduction  of  the  pressure  of  the  air 
contained  in  the  pipe  from  15  to  14  pounds  per  square  inch,  there 
will  be  (unless  the  water  ascended  the  pipe)  an  unequal  press- 
ure upon  its  surface  inside  as  compared  to  that  outside  of  the 
pipe ;  but,  in  ^consequence  of  the  water  rising  2i  feet  in  the  pipe, 
the  pressure  on  the  surface  of  the  water,  both  inside  and  outside. 
34*  2A 


402 


THE    engineer's  HANDY-BOOK. 


is  evenly  balanced  (taking  the  level  of  the  outside  water  to  be  the 
natural  level  of  the  water  inside),  as  the  pressure  upon  the  water 
exposed  to  the  full  atmosphere  is  15  pounds  upon  each  square 
inch  of  its  surface,  while  that  upon  the  same  plane,  but  within 
the  pipe,  will  sustain  a  column  of  water  2}  feet  high  (weighing 
one  pound)  and  14  pounds  pressure  of  air,  making  a  total  of  15 
pounds,  which  is,  therefore,  an  equilibrium  of  pressure  over  the 
whole  surface  of  the  water  at  its  natural  level. 

If,  in  consequence  of  a  second  stroke  of  the  pump,  the  air 
pressure  in  the  pipe  is  reduced  to  13  pounds  per  inch,  the  water 
will  rise  another  2}  feet.  This  rule  is  uniform,  and  shows  that 
the  rise  of  a  column  of  water  within  the  pipe  is  equal  in  weight 
to  the  pressure  of  the  air  upon  the  surface  of  the  water  without ; 
hence  it  is  only  necessary,  to  determine  the  height  of  a  column  of 
water  that  will  weigh  15  pounds  per  square  inch  of  area  at  the 
base,  to  ascertain  how  far  a  suction-pump  will  cause  the  water  to 
rise.  It  must  be  understood,  that  the  distance  varies  with  the 
height  above  sea  level,  and  also  with  the  pressure  of  the  atmos- 
phere. At  our  level  of  the  sea,  the  column  of  water  that  the 
atmosphere  will  support  is  about  33  feet  in  height,  and  a  pump 
will  draw' water''  (as  it  is  called)  this  distance;  but  the  force 
which  sends  the  water  into  the  pump  at  this  height  is  so  dimin- 
ished as  to  be  almost  balanced  by  its  own  weight ;  hence  a  lifting- 
pump  will  deliver  water  very  slowly,  drawing  it  this  distance. 

To  be  reliable,  the  cylinder  and  piston  should  be  in  good  order, 
all  the  joints  perfectly  air-tight,  a  check-valve  be  placed  in  the 
lower  end  of  the  suction-pipe ;  and  even  then  the  pumps  should 
be  run  at  a  high  speed.  Pumps  will  give  more  satisfactory  results 
when  the  lift  is  from  22  to  25  feet.  There  is  hardly  any  limit  to 
the  distance  a  pump  will  draw  water  through  a  horizontal  suction- 
pipe,  provided  the  pipe  is  perfectly  tight,  and  everything  is  so  pro- 
portioned as  not  to  cause  undue  friction. 

The  capacity  of  any  pump  may  be  determined  by  multiplying 
the  area  of  the  piston  in  inches  by  its  stroke  in  inches,  giving  the 
number  of  cubic  inches  per  single  stroke ;  this  divided  by  231  (the 


THE   engineer's  HANDY-BOOK. 


403 


number  of  cubic  inches  in  a  standard  gallon)  will  give  the  number 
of  gallons  per  single  stroke ;  but  it  must  be  remembered  that  all 
pumps  throw  less  water  than  their  capacity,  the  deficiency  rang- 
ing from  20  to  40  per  cent.,  according  to  the  quality  of  the  pump. 
This  loss  arises  from  the  lift  and  fall  of  the  valves,  from  inaccuracy 
of  fit  or  leakage,  and  in  many  cases'from  there  being  too  much  space 
between  the  valves  and  piston,  or  plunger.  The  higher  the  valves 
of  any  pump  have  to  lift  to  give  the  necessary  opening,  the  less 
efl[icient  the  pump  will  be. 

The  power  required  to  raise  a  given  quantity  of  water  a  certain 
height  may  be  computed  by  the  following  rule:  Multiply  the 
amount  of  water  in  gallons  to  be  raised  per  minute  by  8'35  lbs. 
(the  weight  of  a  gallon  of  water),  and  this  product  by  the  height,  in 
feet,  of  the  discharge  from  the  point  of  suction ;  divide  the  result  by 
33,000,  which  will  give  the  theoretical  horse-power  required  to  raise 
the  amount  of  water  to  a  certain  distance.  See  table  on  page  522. 

The  quantity  of  water  which  any  pump  will  lift,  or  discharge, 
may  be  estimated  by  multiplying  the  area  of  the  piston  by  the 
speed ;  but  this  rule  infers  that  the  pump  is  fully  supplied,  and 
the  water  thoroughly  discharged  at  every  stroke. 

Rule  for  finding  the  diameter  of  pump-plunger  for  any  engine. — 
•When  the  pump-stroke  is  ^  the  stroke  of  the  engine,  the  diameter 
of  the  steam-cylinder  multiplied  by  0*3  will  give  the  proper  di- 
ameter of*  pump-plunger. 

Another  rule. —  When  the  pump-stroke  is  \  of  the  stroke  of  the 
engine,  the  diameter  of  the  cylinder  multiplied  by  '42  will  give 
the  proper  diameter  of  pump-plunger. 

Diameter  of  pump-plunger  should  be  equal  to  |  the  diameter 
of  the  cylinder  ^yhen  the  pump-stroke  is  h  the  engine-stroke. 

Diameter  of  pump-plunger  should  be  equal  to  J  of  the  diameter  of 
the  cylinder  when  the  pump-stroke  is  \  the  engine-stroke.  The  ve- 
locity of  water  in  pump-passages  should  not  exceed  500  feet  per  min- 
ute. Pump-valves  should  have  an  area  of  |  the  area  of  the  pump. 

Feed-pumps  for  condensing  engines: — For  condensing  engines, 
the  diameter  of  the  pump-plunger  should  equal  1*11  the  diameter 


404         THE  engineer's  handy-book. 

of  the  steam-cylinder  when  the  pump-stroke  is  half  the  engine- 
stroke,  and  ^  the  diameter  of  steam-cylinder  when  the  pump-stroke 
is  I  the  stroke  of  the  engine. 

Rule  to  find  the  diameter  of  the  feed-pump  ram. —  Multiply 
the  square  of  the  diameter  of  the  cylinder  in  inches  by  *0083. 
The  product  is  the  diameter  of  the  ram  in  inches.  All  boiler 
feed-pumps,  when  working,  at  ordinary  speed,  should  be  capable 
of  discharging  one  cubic  foot  of  water  per  horse-power  per  hour. 

Rule  for  finding  the  necessary  quantity  of  water  per  minute  for 
any  engine. —  Multiply  the  cubic  space  in  the  cylinder  in  inches, 
to  which  steam  is  admitted  before  being  cut  off,  by  twice  the  num- 
ber of  revolutions  per  minute,  and  divide  the  product  by  the  com- 
parative volume  of  steam  at  the  pressure  used ;  the  quotient  will  be 
the  cubic  inches  of  water  required  per  minute. 

A  circulating-pump  is  used  to  lift  water  from  the  sea  and  force 
it  through  the  condenser.  Such  pumps  are  not  always  worked  by 
the  main  engines,  but  sometimes  are  independent  or  worked  by  an 
independent  auxiliary  engine.    See  cut  on  page  352. 

Although  a  pump  will  require  to  be  in  good  condition  to  lift 
water  33  feet,  it  will  with  ease  draw  water  on  a  level  at  1000  feet 
(providing  the  pipes  are  all  tight),  and  force  it  to  any  height  that 
the  machinery  of  the  pump  is  capable  of  bearing. 

The  reason  why  pumps  do  not  work  is,  either  that  the  water- 
supply  is  exhausted,  the  pipes  or  pistons  leak,  or  the  valves  pre- 
vented from  seating.  If  the  valves  and  connections  of  a  pump 
are  tight  and  in  good  order,  and  it  is  not  located  too  high  above 
the  supply,  there  is  no  reason  why  it  should  not  work. 

Pumps  become  hot  from  two  reasons, — either  they  are  placed 
too  near  the  boiler,  or  the  pump  and  check-valves  Jeak,  and  allow 
the  hot  water  to  escape  back  from  the  boiler  into  the  barrel  of  the 
pump,  which  has  the  effect  of  expanding  the  valves  and  prevent- 
ing them  from  doing  their  work. 

A  boiler  feed-pump,  or  injector,  for  any  engine  should  be  capa- 
ble of  supplying  one  cubic  foot  of  water  per  horse-power  per  hour. 
Engines,  in  general,  do  not  use  that  amount ;  in  fact,  the  better 


THE   ENGINEER\s  HANDY-BOOK. 


405 


class  of  automatic  cut-off  engines  will  develop  a  horse-power  with 
a  water-consumption  of  from  25  to  30  lbs. ;  but  it  is  always  best 
to  have  the  pump  or  injector  sufficiently  large,  so  that,  in  case  the 
power  should  be  increased,  it  may  be  equal  to  the  demand. 

An  air-chamber  is  placed  on  a  pump  to  cushion  the  water-piston, 
and  relieve  the  jar  that  would  be  induced  by  the  pump-piston 
striking  against  a  solid  column  of  water ;  but,  to  produce  the 
desired  effect,  it  must  be  perfectly  air-tight,  otherwise  the  air 
will  escape.  Even  when  the  air-chamber  is  perfectly  air-tight, 
they  require  to  be  frequently  refilled,  as  in  fast-running  pumps 
and  fire-engines  the  air  becomes  condensed.  This  may  be  done 
by  stopping  the  engine  or  pump,  opening  a  cock  or  valve  that 
connects  with  it,  and  allowing  the  air  to  rush  in.  There  is  a  very 
general  impression  among  engineers  and  those  having  charge  of 
fire-engines,  that  there  is  a  vacuum  in  the  air-chamber,  and  the 
remark  is  often  heard  that  the  pump  or  engine  has  lost  its  vacuum. 
This  is  a  mistake,  as  there  is  no  such  thing  as  a  vacuum  in  the 
air-chamber  of  a  steam-pump  or  fire-engine.  The  air-chamber 
has  lost  its  supply  of  air  either  by  leakage  or  condensation.  The 
result  is  the  pump  commences  to  work  and  labor. 

A  feed-pump  pet-cock,  or  valve,  is  a  small  cock,  generally 
placed  on  the  barrel  of  the  pump  above  the  suction-valve,  for  the 
purpose  of  ascertaining  whether  the  pump  is  working  right  or  not. 

Mud-boxes,  strainers,  or  arresters  should  be  attached  to  the 
extreme  end  of  all  lift-,  suction,-  bilge-,  or  circulating-pumps,  for 
the  purpose  of  arresting  any  matter  that  would  be  liable  to  choke 
the  pump  or  prevent  the  valve  from  seating. 

How  to  keep  pipes  and  pumps  from  freezing.— The  only  certain 
preventive  is  the  removal  of  the  water  from  them ;  consequently, 
in  all  cases  provision  should  be  made  for  turning  it  off  during 
very  severe  nights.  It  must  be  observed,  however,  that  merely 
J  shutting  off  the  water  is  not  sufficient ;  it  must  all  be  let  out  of 
the  pipes.  For  this  purpose  a  small  tap  or  pet-cock  should  be 
I  placed  above  the  main  stop-cock,  or  the  latter  should  be  made 
with  a  vent,  to  allow  the  water  to  flow  out  when  it  is  turned  off. 


t06 


THE   ENGINEER'S  HANDY-BOOK. 


Injectors. 

The  injector,  though  simple  in  design,  modest  in  appearance, 
and  diminutive  in  size,  is,  nevertheless,  one  of  the  most  wonderful, 
important,  and  useful  machines  which  the  mechanical  arts  have 
ever  presented  to  man.  It  consists  of  a  slender  tube,  called  the 
steam-tube,  through  which  steam  from  the  boiler  passes  to  another 
or  inner  tube,  called  the  receiving-tube.  The  latter  tube  conducts 
a  current  of  water  from  the  pipe  into  the  body  of  the  injector. 
Opposite  the  mouth  of  this  second  tube,  and  detached  from  it,  is 
a  third  fixed  tube,  called  the  delivery-tube.  This  tube  is  open  at 
the  end  facing  the  water-supply  and  leading  from  the  injector  to 
the  boiler. 

Its  action  is  identical  to  that  of  the  steam-jet,  or  blower-pipe  in 
the  chimney  of  the  locomotive.  The  principle  is,  that  steam  being 
admitted  to  the  inner  tube  of  the  injector,  enters  the  mouth  of  a 
combining-tube  in  the  form  of  a  jet,  near  the  top  of  the  inlet  water- 
pipe.  If  the  level  of  the  water  be  below  the  injector,  the  escaping 
jet  of  steam,  by  its  superficial  action  (or  friction)  upon  the  air 
^iround  it,  forms  a  partial  vacuum  in  the  combining-tube  and  inlet- 
pipe,  and  the  water  then  rises  by  virtue  of  the  external  pressure  of 
the  atmosphere.  Once  risen  to  the  jet,  the  water  is  acted  upon  by 
the  steam  in  the  same  manner  as  the  air  has  been  seized  and  acted 
upon  in  first  forming  the  partial  vacuum  into  which  the  water  rose. 

Giffard  was  the  first  to  make  a  practical  application  of  the  prin- 
ciples embodied  in  the  injector ;  in  fact,  when  he  invented  his  in- 
jector, he  may  be  said  to  have  invented  them  all.  His  discovery 
was,  that  the  motion  imparted  by  a  jet  of  steam  to  a  surrounding 
column  of  water  was  sufficient  to  force  it  into  the  boiler  from 
which  the  steam  was  taken,  and,  indeed,  into  a  boiler  working  at 
even  a  higher  pressure.  It  is  not  at  all  extraordinary  to  see  in- 
jectors, attached  to  boilers  carrying  a  pressure  of  70  or  80  lbs.  per 
square  inch,  forcing  water  into  other  boilers  under  a  pressure  of 
250  lbs.  per  square  inch.  This  extraordinary  accumulation  of 
power  may  be  explained  as  follows :  the  velocity  with  which  steam 


THE   ENGINEER\s  HANDY-BOOK. 


407 


—  say  at  60  lbs.  pressure  to  the  square  inch  —  flows  into  the  atmos- 
phere is  about  1700  feet  per  second.  Now  suppose  that  steam  is 
issuing,  with  the  full  velocity  due  to  the  pressure  in  the  boiler, 
through  a  pipe  an  inch  in  area,  the  steam  is  condensed  into  water, 
at  the  nozzle  of  the  injector,  without  suffering  any  change  in  its 
velocity.  From  this  cause  its  bulk  will  be  reduced,  say  1000, 
and  therefore  its  area  of  cross-section  —  the  velocity  being  constant 
— will  experience  a  similar  reduction.  It  will  then  enter  the  boiler 
by  an  orifice  j^^n  P^^^  ^^^^^  ^7  which  it  escaped.  Now  it  will 
be  seen  that  the  total  force  expended  by  the  steam  through  the 
pipe  on  the  area  of  an  inch,  in  expelling  the  steam-jet,  was  con- 
centrated upon  the  area  y^\~)  o"  of  an  inch,  and  therefore  was  greatly 
superior  to  the  opposing  pressure  exerted  upon  the  diminished  area. 

The  invention  of  the  Giffard  Injector,  like  that  of  the  Corliss 
engine,  suggested  a  numerous  progeny.  This  may  be  seen  from  the 
numerous  cuts  of  that  class  of  machines  illustrating  this  work,  but 
Sellers'  Injector  is  the  only  one  that  can  be  said  to  be  an  improve- 
ment on  Giffard's.  All  the  others  are  simply  modifications  of  the 
original  Giffard  instrument,  some  few  bringing  out  features  which 
had  not  been  contemplated  by  Giffard,  who  considered  Wm.  Sell- 
ers' improvements  the  only  ones  that  had  been  made  upon  his  in- 
strument. 

Injectors  may  be  divided  into  three  classes  —  "  self-adjusting," 
"adjustable,"  and  "fixed-nozzle."  The  self-adjusting  injector  reg- 
ulates itself  to  meet  all  the  conditions  under  which  it  is  intended 
to  work,  and,  once  started,  it  will  work  under  a  variation  of  steam- 
pressure  of  from  10  to  150  lbs.  This  kind  of  injector  furnishes 
the  most  reliable  boiler-feeder.  The  adjustable  wjedor  is  one  in 
which  the  nozzle  can  be  adjusted  to  meet  the  requirements  of  vary- 
ing steam-pressure  and  water-supply.  Such  injectors  are  capable 
of  high  duty  when  skilfully  managed.  The  original  Giffard  rep- 
resents this  type  of  injector. 

The  injector  possesses  many  advantages  as  a  boiler-feeder  for 
furnishing  large  quantities  of  water,  supplying  tanks,  etc.  Its  first 
cost  is  moderate,  it  occupies  but  little  space,  and  requires  no  oil, 


408 


THE   engineer's  HANDY-BOOK. 


packing,  or  repairs.  It  can  be  set  up  almost  anywhere  and  placed 
either  vertically  or  horizontally  ;  the  latter  position,  however,  is 
preferable.  It  will  act  longer,  and  perform  more  work  even 
when  abused  and  neglected,  than  any  other  device  heretofore 
invented  as  a  boiler-feeder. 

William  Sellers  &  Co.'s  Injector. 

The  cut  on  page  409  represents  Sellers'  celebrated  lifting  in-, 
jector,  so  extensively  used  on  locomotives,  steamships,  tugs,  and 
ferries.  It  is  a  self-contained  instrument,  that  is  to  say,  it  has 
both  steam-  and  check-valves;  so  that  it  can  be  connected  directly, 
without  any  other  fittings ;  although,  of  course,  it  is  desirable  to 
place  another  stop-valve  in  the  steam-pipe  and  a  check-valve  in 
the  delivery-pipe,  so  that  the  injector  can  be  taken  to  pieces,  or 
disconnected  at  any  time.  Another  important  feature  of  this  in- 
jector is,  that  it  is  operated  by  a  single  handle,  and  that  the  waste- 
valve  is  only  open  at  the  instant  of  starting. 

Its  internal  mechanism  and  mode  of  action  may  be  easily  un- 
derstood by  referring  to  the  sectional  cut  on  page  410.  A  is  the 
receiving-tube,  which  can  be  clgsed  to  the  admission  of  steam  by 
the  valve  X  A  hollow  spindle  passing  through  the  receiving- 
tube  into  the  combining-tube,  is  secured  to  the  rod  B,  and  the 
valve  X  is  fitted  to  this  spindle  in  such  a  way  that  the  latter  can 
be  moved  a  slight  distance  (until  the  stop  shown  in  the  figure 
engages  with  valve  X)  without  raising  the  valve  X  from  its  seat. 
A  second  valve,  TT,  secured  to  the  rod  By  has  its  seat  in  the  upper 
side  of  the  valve  X,  so  that  it  can  be  opened  (thus  admitting  steam 
to  the  centre  of  the  spindle)  without  raising  the  valve  X  from  its 
seat,  if  the  rod  B  is  not  drawn  out  any  farther  after  the  stop  on 
the  hollow  spindle  comes  in  contact  with  the  valve  X.  D  is  the 
delivery-tube,  0  an  overflow  opening  into  space  C  K,  the  check- 
valve  in  delivery-pipe,  and  P  R  the  waste-valve.  The  upper  end 
of  the  combining-tube  has  a  piston,  N  N,  attached  to  it,  capable 
of  moving  freely  in  a  cylindrical  portion  of  the  shell,  M  and 


35 


THE   ENGINEER'S  HANDY-HOOK. 


411 


the  lower  end  of  the  combining-tube  slides  in  a  cylindrical  guide 
formed  in  the  upper  end  of  the  delivery-tube. 

The  rod  B  is  connected  to  a  cross-head  which  is  fitted  over 
*.he  guide-rod,  «7,  and  a  -lever,  //,  is  secured  to  the  cross-head.  A 
vod,  L,  attached  to  a  lever  on  the  top  end  of  the  screw  waste-valve 
lj»asses  through  an  eye  that  is  secured  to  the  lever  // ;  and  stops, 
r,  control  the  motion  of  this  rod,  so  that  the  waste-valve  is 
Josed  when  the  lever  H  lias  its  extreme  outward  throw,  and  is 
Apened  when  the  lever  is  thrown  in,  so  as  to  close  the  steam-valve, 
X,  while  the  lever  can  be  moved  between  the  positions  of  the  stops, 
P,  Q,  without  affecting  the  waste-valve.  A  latch,  F,  is  thrown 
into  action  with  teeth  cut  in  the  upper  side  of  the  guide-rod,  J, 
when  the  lever  ^is  drawn  out  to  its  full  extent,  and  then  moved 
back ;  and  this  click  is  raised  out  of  action  as  soon  as  it  has  been 
moved  in  far  enough  to  pass  the  last  tooth  on  the  rod  J.  An  air- 
vessel  is  arranged  in  the  body  of  the  instrument,  as  shown  in  the 
figure,  for  the  purpose  of  securing  a  continuous  jet  when  the  in- 
jector and  its  connections  are  exposed  to  shocks,  especially  such 
as  occur  in  the  use  of  the  instrument  on  locomotives. 

The  manipulation  required  to  start  the  injector  is  exceedingly 
simple, —  much  more  so  in  practice,  indeed,  than  it  can  be  rendered 
in  description.  Moving  the  lever  H  until  contact  takes  place  be- 
tween valve  X,  and  stop  on  hollow  spindle,  which  can  be  felt  by 
the  hand  upon  the  lever,  steam  is  admitted  to  the  centre  of  the 
spindle,  and,  expanding  as  it  passes  into  the  delivery-tube  D,  and 
waste-orifice  P,  lifts  the  water  through  the  supply-pipe  into  the 
combining-tube  around  the  hollow  spindle,  acting  after  the  manner 
of  an  ejector  or  steam-siphon.  As  soon  as  solid  water  issues  through 
the  waste-orifice  P,  the  handle  jETmay  be  drawn  out  to  its  full  ex- 
tent, opening  the  steam- valve  X  and  closing  the  \vaste-valve,  when 
the  action  of  the  injector  will  be  continuous  as  long  as  steam  and 
water  are  supplied  to  it. 

To  regulate  the  amount  of  water  delivered,  move  in  the  lever 
H  until  the  click  engages  any  of  the  teeth  on  the  rod  J,  thus 
diminishing  the  steam-supply,  as  the  water-supply  is  self-regulat- 


412 


THE   engineer's  HANBY-BOOK. 


ing.  If  too  much  water  is  delivered,  some  of  it  will  escape  through 
0  into  C,  and,  pressing  on  the  piston  N  N,  will  move  the  com- 
bining-tube  away  from  the  delivery-tube,  thus  throttling  the  water- 
supply  ;  and  if  sufficient  water  is  not  admitted,  a  partial  vacuum 
will  be  formed  in  C,  and  the  unbalanced  pressure  on  the  upper  side 
of  the  piston,  N  N,  will  move  the  combining-tube  towards  the  de- 
livery-tube, thus  enlarging  the  orifice  for  the  admission  of  water. 
The  injector,  once  started,  will  continue  to  work  without  any  further 
adjustment,  delivering  all  its  water  to  the  boiler,  the  waste-valve 
being  kept  shut.  By  placing  the  hand  on  the  starting-lever,  it  is 
easy  to  tell  whether  or  not  the  injector  is  working ;  and  if  desired, 
the  waste-valve  can  be  opened  momentarily  by  pushing  the  rod  Ly 
a  knob  on  the  end  being  provided  for  the  purpose. 

TABLE 


SHOWING  STEAM-PRESSURE  REQUIRED  TO  LIFT  AND  DELIVER  WATER  WITH 
sellers'  FIXED-NOZZLE  LIFTJLNG  INJECTOR. 




Height  Wa- 
ter IS  LIFTED. 

Steam-Peess- 
ure  required 
to  lift  and  de- 
LIVER WaTER. 

Height  Wa- 
ter IS  lifted. 

Steam-Press- 
ure REQUIRED 
TO  LIFT  AND  DE- 
LIVER Water. 

Feet.  Inches. 
3  0 
5  0 
11  6 
15  0 

Lbs.  per  Sq.  In. 
25 
30 
40 
49 

Feet.  Inches 

21  3 

22  10  ■ 

Lbs.  per  Sq.  In. 
52 
60 
70 
100 

Sellers'  Non- Adjusting  Fixed-Nozzle  Injector  with  Lifting 
Attachment,  for  Stationary  Boilers. 

The  cut  on  page  413  represents  Sellers'  Non- Adjustable  In- 
jector with  fixed-nozzle  and  lifting  attachment  As  will  be  ob- 
served, a  steam-ejector  or  siphon  is  attached  to  the  side  of  this 
instrument,  which  draws  the  water,  when  lifted  by  the  admission 
of  the  steam,  through  the  combining-tube,  and  discharges  it 
through  the  orifice  of  the  lifting  attachment,  through  which,  also, 


THE   engineer's    H  A  N  I>  Y  -  B  O  O  K  . 


413 


the  waste  water  or  overflow  escapes.  This  injector  has  a  check- 
valve  connected  to  it,  also  a  steam  stop-valve,  which  can  be  opened 
wide  by  half  a  revolution  of  the  lever  on  the  stem.  In  connecting 
the  injector,  since  it  has  fixed  nozzles,  a  water-supply  valve  must 
be  provided,  and,  as  al- 
ready remarked,  a  sec-  b\ 
ond  check-valve  in  the 
delivery  -  pipe  and  an- 
other steam-stop  valve 
are  desirable. 

In  starting  this  injec- 
tor, steam  is  first  admit- 
ted to  the  lifting-nozzle, 
the  water-supply  valve 
being  adjusted  so  as  to 
deliver  about  the  max- 
imum amount  of  water 
corresponding  to  the 
steam-pressure;  and  as 
soon  as  solid  water  is- 
sues from  the  lifting- 
nozzle,  the  steam-valve 
is  to  be  opened  slightly 
until  the  jet  is  estab- 
lished, when  the  full 
steam-pressure  is  to  be 
admitted,  and  the  valve 
that  admits  steam  to  the 
lifting-nozzle  is  to .  be 
closed. 

Some  little  dexterity  Section  of  Sellers*  Non- Adjustable  Fixed- 
is  required  to  start  the  Nozzle  Lifting:  Injector, 

injector  for  a  maximum  lift,  but  the  manipulation  is  readily  ac- 
quired, while  for  all  ordinary  lifts  no  special  care  is  required.  As 
the  velocity  of  steam  escaping  from  an  orifice  varies  greatly  with 
35* 


414 


THE   ENGINEER'S  HANDY-BOOK. 


the  pressure,  other  things  beiug  equal,  the  lifting-nozzle  must  have 
proportions  depending  on  the  minimum  steam-pressure  to  be  em- 
ployed, since  it  can  readily  be  adapted  to  higher  pressures  by  par- 
tially closing  the  steam-admission  valve. 

Directions  for  operating  Sellers'  non-adjustable  fixed-nozzle 

injector,  with  lifting  at- 
tachment.— First,  close 
the  steam -spindle,  J., 
by  means  of  the  handle, 
B.  Second,  open  the  lift- 
ing-jet by  backing  the 
wheel,  C,  one-quarter 
turn.  Third,  when  the 
water  escapes  at  the 
overflow,  D,  run  out 
the  spindle,  A ,  by  back- 
ing it  quickly;  then 
close  tjje  lifting-jet,  C, 
as  the  injector  will  then 
be  feeding  the  boiler, 
land  the  water-supply 
'may  be  regulated  by 
means  of  an  ordinary 
globe-valve  placed  be- 
tween the  injector  and 
the  water  source.  If 
this  valve  is  set  to  ad- 
mit the  required  quan- 
tity of  water,  there  will 
be  no  drip  from  the 
overflow.  When  re- 
quired, a  special  regu- 
lating valve,  which  re- 
quires but  one  turn,  and  which  indicates  the  required  opening,  is 
attached  to  the  injector,  so  that  those  having  it  in  charge  may  de- 


Sellers'  Non-Adjustable  Fixed-Nozzle 
Lifting"  Injector. 


THE   engineer's  HANDY-BOOK. 


415 


terniine  the  actual  amount  of  opening  by  a  glance  at  the  hand- 
wheel  on  the  valve-spindle. 

Duty  of  Sellers'  injectors,  or  the  foot-pounds  of  useful  work 
performed  by  the  consumption  of  100  lbs.  of  coal  in  the  boiler 
supplying  steam  to  the  injector,  may  be  of  interest.  When  the 
evaporation  of  the  boiler  is  known,  this  duty  can  readily  be  com- 
puted from  the  data  obtained  in  connection  with  the  maximum 
delivery  of  the  injector.  This  can  be  illustrated  by  an  example. 
Assuming  the  boiler  evaporation  at  9  lbs.  of  steam  per  lb.  of  coal, 
a  result  which,  though  rather  above  the  average,  is  occasionally 
exceeded  in  good  practice.  Using  the  data  recorded  in  the  table 
on  page  416  for  the  maximum  delivery  at  a  steam-pressure  of  130 
lbs.  per  square  inch,  it  appears  that  150  —  66  =  84  units  of  heat 
were  imparted  to  each  pound  of  water  delivered  by  the  injector, 
and,  the  weight  of  a  cubic  foot  of  water  at  a  temperature  of  66° 
Fah.  being  about  62*3  lbs.,  that  the  total  weight  of  water  deliv- 
ered per  hour  was  161*2  X  62*3  =  10,042-76  lbs.,  so  that  the  total 
amount  of  heat  imparted  to  the  water  per  hour  was  10,042*76  x 
84  =  843,591*84  units.. 

The  total  heat  above  32^  in  a  pound  of  dry  steam,  at  a  pressure 
of  130  lbs.  per  square  inch,  is  1187*8  units,  and  the  heat  remain- 
ing in  a  pound  of  steam  above  32°,  after  condensation,  is  150 
—  32  =  118  units,  so  that  each  pound  of  dry  steam  imparted 
1187*8  —  118  =  1069*8  units  of  heat  to  the  feed-water,  and  the 

.1^  1  .  1  843,591*84  r,oon^^ 

weight  01  dry  steam  required  per  hour  was    .^^^^g  ^ —  =  7oo*o  lbs. 

The  height  of  a  column  of  water  equivalent  to  the  pressure  against 

which  the  water  was  delivered  was  =  300*5  feet,  so  that 

bZ'o 

the  useful  work  performed  per  hour  ^vas  10,042*76  x  300*5  = 
3,017,049*38  foot-pounds.    The  weight  of  coal  required  to  do  this 

788*6 

work,  on  the  assumed  boiler  evaporation,  was  ~— -  =  87*6  lbs., 

so  that  the  duty  of  the  injector,  per  100  lbs.  of  coal,  was 

3,017,049*38  x  100     oiKR^oa,-  ,  a 
'  g^^Tg — ~  =  3,455,536  loot-pounds. 


416 


THE   engineer's  HANDY-BOOK. 


The  term  range  is  frequeDtly  used  in  connection  with  injectors, 
and  means  the  difference  between  the  maximum  and  minimum 
delivery. 

TABLE 

SHOWING  THE   MAXIMUM  AND  MINIMUM   DELIVERY  OF  SELLERS^  SELF- 
ADJUSTING,  1876,  INJECTOR  NO.  6  ;    temperature  of  delivered 

WATER  ;  PRESSURE  AGAINST  WHICH  INJECTOR  DELIVERS  WATER,  AND 
HIGHEST  TEMPERATURE  OF  FEED  ADMISSIBLE  ;  WATER  FLOWING  TO 
INJECTOR  UNDER  15  INCHES  HEAD  ;  WASTE-VALVES  SHUT. 


Pressure  of  Steam  Supplied  to 
Injector,  and  Pressure  against 
which  Water  is  Delivered. 
Lbs.  per  Sq.  In. 

Delivery  in  Cubic 
Feet  Per  Hour. 

Temperature  Fahren- 
heit Degrees. 

Pressure  of  Steam  Required  to 
Deliver  Water  against  Press- 
ure in  Column  1. 

Highest  Temperature  admissible 
of  Feed-Water,  Fahrenheit 
Degrees. 

Maximum. 

Minimum. 

Ratio  of  Minimum  to 
Maximum  Delivery. 

Feed-Water. 

Deli\ 
Wa 

s 
a 

''ERED 
PER. 

u 

D 

% 
M 

<  a 
1 

1 

2 

3 

4 

5 

0 

7 

8 

9 

10 

75-3 

63-6 

0-845 

66 

100 

94 

3 

132 

20 

82-4 

61-2 

0-743 

66 

108 

104 

9 

134 

30 

94-2 

56-5 

0-600 

66 

114 

116 

16 

134 

40 

100-1 

60-0 

0-599 

66 

120 

123 

22 

132 

50 

108-3 

64-7 

0-597 

66 

124 

125 

27 

131 

60 

116-5 

63-6 

0-546 

66 

127 

133 

34 

130 

70 

124-8 

63-6 

0-510 

67 

130 

142 

40 

130 

80 

133-0 

67-1 

0-505 

66 

134 

144 

46 

131 

90 

141-3 

69-5 

0-492 

67 

136 

148 

52 

132 

100 

147-2 

64-7 

0-456 

66 

140 

159 

58 

132 

110 

153-0 

67-1 

0-439 

67 

144 

162 

63 

132 

120 

156-6 

73-0 

0-466 

67 

148 

162 

69 

134 

130 

161-2 

74-2 

0-460 

66 

150 

165 

75 

130 

140 

166-0 

78-9 

0-476 

66 

153 

166 

81 

126 

150 

170-7 

70-6 

0-414 

66 

157 

167 

88 

121 

The  table  of  capacities  shows  the  maximum  delivery,  but  the 
injector  can  be  regulated  so  as  to  reduce  the  amount  about  60  per 
cent 


THE   engineer's    If  A  N  I)  Y  -  H  OO  K  . 


417 


<M  CD      uj  Oi      <?1  00 

CD  C<l  l-^  C»  »p  »p       »p  ^       p  00  CJ 

r-H  r-i  CO  -f  ^  CC  O  CO 


CO  00  CO  CO  CO  Ol 

(pTh»po:>^QO<prru:)pr-i»piOi— I 

coooi^<i>OT^T^a)coi*-i^ooio 
i-icocoo:)^05iOrHO:>cDi-^i-QO 

T-l  r-l  (M  CO  CO  »0  1^  O  01  t  o 


CD      (M  CO  00  1^       CO  GO  I-  CD 

(>1  cp  ^4  cp  CO      00  C-UO  CX)  T-H  C-l  iO  o 

coT^cbc^coc<icbc<icooo»^cn)4foi 
rHcoioc:»coQOcooi.^coco»o»— (c:i 

rHrHCNCOCOiOt-OiO-l'^ 


C^OtJlOt^CDOvlCDCDCOOT-iGOOC:) 
rHC^lOCO<Nt^G^4GOiOi-HC:)0^i— ( 
1— li— i(M(MCOtOCDa5r-iTt 


r-lQ0(MG\|a:i0^1C00iC0rHr-(CDTf'O 
T-HGvllOGOr-iCDi— ICDCOGOIO^OOCO 
T-(T-HG\|G\|C0rtiCDQ0OC0 


1— ICDOilr^i— iC<IOCOCOCvli— (LOCiC:> 
T-ir-iCNKMCO'T^CDOOOO^ 


.  o     00  CO        1^  00  lo 


OrxlMC^lt^t^CO'r^T-HCOrfT-KMaiO 
C<|rtiCDC5COI:^Gvlt^OiCOOOOa:> 

i-HT-^fMcqcoiOt-ooo 


1— (0:)C<10CO(M^COCDT-H,-HlOCi 
(MCOCDO:)GMCDOiOCDC:iOG^^ 
1— lrHC<lC^CO'^CDOOO 


C0O:iCDt-CO'^OiO^C0l:-i— lOOOO 
1— iCOlOOOl— l-^OOCOCO^OCDCO 
r-lT-Hi— iGvlCO'^CDt^Oi 


.2  g 


O 


C<IC0'^^CDl>G00:!O<MTfiCD00O 

-  -  -  — 


P5 

H 
P 

fa 
O 

w 

< 

:^ 

w 


2B 


418 


THE   engineer's  HANDY-BOOK. 


The  reputation  of  the  Sellers'  injectors  stands  deservedly  high 
for  efficiency,  reliability,  and  action.  They  are  adapted  to  all  pur- 
poses for  which  such  instruments  are  employed,  such  as  boiler- 
feeders  for  steamships,  locomotives,  and  stationary  engines.  Every 
injector  is  tested  at  the  works  by  being  attached  to  a  steam-boiler 
before  being  sent  out,  and  tried  under  different  pressures,  which 
insures  entire  satisfaction  in  the  working,  so  that  it  is  sure  to  meet 
all  the  requirements  for  which  it  is  intended. 

Rue's  "  Little  Giant Injector. 

The  annexed  cut  represents  Rue's  "Little  Giant"  Injector,  class 
A,  which,  as  a  boiler-feeder,  has  a  reputation  for  simplicity,  efficien- 


forwards  or  backwards,  as  seems  requisite,  until  neither  steam  nor 
water  shows  at  the  overflow\  When  it  is  ascertained  where  the 
lever  must  be  set,  for  the  steam  carried,  it  can  be  adjusted  before 
beginning,  or  left  as  it  is,  when  steam  is  shut  off.  The  lever  is 
only  used  to  regulate  the  proportionate  amounts  of  steam  and 
water.  The  injector  will  feed  one-half  its  capacity,  by  decreasing 
the  amount  of  steam,  and  then  adjusting  the  lever.  By  a  little 
practice,  any  engineer  can  adjust  it,  so  as  to  feed  a  steady  stream 
of  exactly  the  amount  necessary  for  use. 


cy,  and  capacity  second 
to  no  other  in  the  coun- 
try. All  that  is  neces- 
sary to  be  done  in  order 
to  start  it,  is  to  turn  on 
the  water,  and,  when  it 


flows  from  the  overflow, 
*  turn  on  the  steam,  slowly 
at  first,  until  it  reaches 
the  water,  then  turn  on 
full  head,  and  push  the 
lever  M  slowly,  either 


THE   ENGINEER\s  HANDY-BOOK. 


419 


To  set  up  Class  A. —  Place  the  injector  in  a  horizontal  position, 
at  any  convenient  point,  so  that  the  pipes  will  be  as  short  and 
straight  as  possible.  Place  an  ordinary  globe-valve  on  the  steam- 
pipe  ;  attach  the  steam-pipe  to  the  swivel  marked  steam,  and  the 
water-pipe  to  that  marked  water ;  place  a  valve  or  stop-cock  on 
the  same,  as  near  the  injector  as  practicable.  If  the  water-sup- 
ply is  from  a  tank,  let  the  fall  be  as  great  as  possible,  but  if 
from  a  hydrant,  or  any  other  source  haying  a  pressure  which  is 
not  regular,  as  is  frequently  the  case,  let  the  water-pipe  be  one  size 
larger  than  the  swivel,  and  attach  it  to  the  latter  by  a  reducer. 
Attach  the  delivery-pipe  to  the  swivel  marked  —  "  to  boiler.'' 

The  following  cut  represents  the  Little  Giant"  Lifting  Injec- 
tor, class  B,  which  is  used  for  locomotives  and  steamships,  and  will 
lift  water  12  feet  at  40 
lbs.  pressure.  This  in- 
jector, whether  used  on  a 
locomotive  or  steamship, 
should  be  conveniently 
located  to  the  engineer. 
The  method  of  working 
it  is  identical  with  that 
of  class  A,  except  that 
the  steam-jet  valve  should 
be  first  opened,  then  the 
water  turned  on,  and, 
when  it  appears  at  the 
overflow,  the  main  steam  supply-valve  should  be  opened  gradually 
until  it  catches  the  water,  when  it  may  be  turned  on  full  head. 
The  steam  for  them  should  be  taken  from  the  highest  point  in 
the  boiler,  so  that  it  may  be  dry  and  elastic.  Great  care  should 
be  taken  to  see  that  the  water-pipes  are  all  perfectly  tight.  No 
washers  should  be  used  on  the  swivels  by  which  the  steam-  and 
water-supply  pipes  are  attached  to  the  injector.  If  there  are  any 
floating  particles,  su.ch  as  sawdust,  shavings,  straw,  bran,  or  chai£ 


420 


THE   ENGINEER'S  HANDY-BOOK. 


in  the  water,  the  end  of  the  pipe  should  be  covered  with  a  wire- 
strainer. 

To  start  the  lifting  injector,  Class  B,  open  the  jet-valve  until 
water  shows  at  the  overflow  in  a  solid  stream ;  then  turn  on  the 
steam  as  before,  and,  when  the  water  is  entering  the  boiler,  shut 
the  jet.  Great  care  should  be  taken  to  see  that  the  supply-pipe, 
through  which  the  water  is  lifted,  is  perfectly  air-tight,  as  any 
leak  in  the  pipe  will  interfere  with  the  working  of  the  injector. 
When  water  is  to  be  lifted  by  this  injector,  a  small  steam-pipe 
leading  from  the  boiler,  and  furnished  with  a  valve  that  opens 
with  a  quick  motion,  is  attached  to  the  swivel,  P,  by  means  of 
which  a  steam-jet  is  thrown  into  the  tube,  i?,  and  the  water  lifted. 

TABLE 


OF  CAPACITIES  OF  RUE'S  "LITTLE  GIANT "  INJECTOR. 


Size  of 
Injectors. 

Size  of 
Pipe  Con- 
nections. 

Pressure 
OF  Steam 
IN  Pounds. 

Gallons 
PER  Hour. 

Nominal 
Horse- 
Power. 

0 

4 

90 

60 

4  to  8 

1 

1 

90 

90 

6  "  12 

2 

1 

90 

120 

8  "  20 

3 

3 
4 

90 

300 

20  "  40 

4 

1 

90 

600 

40  "  80 

5 

li 

90 

900 

60  "  120 

6 

U 

90 

1200 

80  "  160 

7 

u 

90 

1620 

140  "  225 

8 

2 

90 

2040 

200  "  275 

9 

2 

90 

2480 

250  "  350 

10 

2 

90 

3000 

300  "  400 

12 

2h 

90 

3600 

350  "  600 

Friedman's  Injector. 

The  annexed  cuts  represent  the  Friedman  Injector,  which 
is  adapted  to  a  great  variety  of  purposes,  such  as  raising  water 


THE   ENGINEER^S  HANDY-BOOK. 


421 


or  other  fluids  from  tanks,  wells,  mines,  quarries, cellars,  docks,  the 
holds  of  vessels,  etc.  They  have  also  been  successfully  employed 
in  breweries,  distilleries,  chemical  works,  and  sugar  refineries,  foi 
conveying  acids,  fluids,  or  liquids  from  tank  to  tank,  or  from 
one  room  to  another.  In  general  appearance  the  injector  is  of 
cylindrical  form,  with 
three  openings,  as  in  all 
others ;  one  of  each  for 
the  suction,  steam,  and 
delivery.  As  will  be  ob- 
served, as  in  all  other  in- 
jectors, instead  of  one 
nozzle  or  cone  there  are 
a  series  in  this  injector  ;  in  this  arrangement  lies  the  secret  of  its 
capacity  and  utility. 

As  the  steam -jet  acts  at  first  only  on  that  portion  of  the  in- 
coming water  which  is  admitted  through  the  first  nozzle,  or  cone, 
so  that  only  a  comparatively  small  jet  of  steam  is  required  to 
move  it,  this  stream, 

propelled    by    the  3  ]  (  O 

force  of  the  steam, 
gives  an  impetus  to 
the  water  entering 
through  the  second 
cone,  and  that  in 
turn  becomes  a  mo- 
tor to  the  next,  and  so  on  until  the  last  is  reached.  The  water 
or  liquid  accelerated  in  its  passage  through  these  successive  noz- 
zles or  cones,  as  well  by  the  force  already  described  as  by  the 
vacuum  always  formed  under  such  conditions,  is  carried  with  great 
velocity  through  the  diverging-pipe  into  the  discharge-pipe,  with 
all  the  force  and  rapidity  necessary  to  convey  it  to  its  required 
destination. 
36 


Section  of  Friedman's  Injector. 


422         THE  engineer's  handy-book. 


TABLE 

OF  CAPACITIES  OF  FRIEDMAN'S  INJECTORS. 


Size  of 
Injec- 
tor. 

Minimum 
Inside 
Diame- 
ter OF 
Pipe  in 
Inches. 

Delivery  per  Hour,  in  Gallons,at  a  Steam- 
Pressure  OP 

k(\  1h« 

m\  Ihe 

JNo.  L 

1 

art 

DO 

oy 

H  O 

3 
4 

220 

180 

141 

90 

4 

-1 
1 

390 

320 

243 

160 

0 

i  1 

li 

630 

500 

395 

250 

"  6 

11 

870 

720 

570 

360 

"  7 

U 

1200 

965 

774 

500 

8 

U 

1560 

1280 

910 

639 

"  9 

2 

1980 

1620 

1380 

810 

"  10 

2 

2450 

2000 

1580 

990 

"  12 

2i 

2870 

2880 

2275 

1440 

The  Keystone  Injector. 

The  above  cut  represents  the  Keystone  Injector,  class  A, 
which  is  used  for  feeding  boilers  where  the  water-supply  is  re- 
ceived from  street-mains,  reservoirs,  cisterns,  etc.    It  should  be 


THE   ENGINEER^S  HANDY-BOOK. 


423 


placed  in  a  horizontal  position,  and,  if  the  water  is  taken  from  a 
tankj^the  injector  should  be  below  the  supply.  All  connections, 
whether  for  steam  or  water,  should  be  of  the  same  internal  bore 
as  the  nipples  on  the  injector.  The  steam  should  be  taken  from 
the  highest  part  of  the  boiler,  in  order  that  it  may  be  dry,  and  the 
pipes  should  be  as  short  and  straight  as  possible,  and  should  not 
be  connected  with  any  supply-pipe  or  feeder  employed  for  any 
other  purpose.  A  globe-valve  should  be  placed  on  both  the  steam- 
and  water-pipes,  but  no  extra  check-valve  is  necessary,  except  the 
one  in  the  swivel,  which  controls  the  outlet  to  the  boiler ;  nor  is 
any  washer  or  packing  necessary  for  any  part  of  the  injector  or 
its  connections,  as  all  of  its  joints  are  ground. 

To  start  the  injector. —  Open  the  steam-valve  for  the  purpose 
of  allowing  any  water  resulting  from  the  condensation  of  steam 
to  escape ;  then  close  it ;  next  open  the  water-cock,  then  the  steam- 
valve,  and  move  the  plug  B  slowly  forward  by  means  of  the 
handle  b,  until  the  water  ceases  to  appear  at  the  overflow.  And 
if,  while  the  injector  is  working,  water  should  commence  to  run 
from  the  overflow,  move  the  plug  slowly  forward  until  the  water 
ceases  to  flow.  If  steam  escapes,  move  the  plug  backward  for  the 
purpose  of  giving  the  injector  more  water.  When  the  lever  b  is 
set,  so  that  the  injector  works  dry,  all  that  is  necessary  to  do  to 
stop  its  feeding  is  to  close  the  steam-valve  first,  then  the  water- 
valve;  and,  when  it  becomes  necessary  to  feed  again,  the  injector 
may  be  started  by  first  opening  the  water-cock  and  then  the  steam- 
valve.  The  lever  being  only  used  to  regulate  the  volume  of  steam- 
and  water-supply,  if  the  lever  moves  too  loosely,  it  may  be  tightened 
by  screwipg  down  the  nut  on  the  spindle  C;  if  too  tight,  the  nut  can 
be  slacked  up.  This  injector  will  work  under  ordinary  circumstances, 
but  there  are  other  injectors  in  the  market  which  are  immensely 
superior  to  them.  , 

The  Keystone  Lifting  Injector. 

The  cut  on  page  424  represents  the  Keystone  Lifting  Injector, 
class  B.  The  same  instructions  for  setting  up  and  manipulating 
class  A,  Fig.  1,  apply  to  this  also,  with  this  exception,  that  no  stop- 


424 


THE   ENGINEER'S  HANBY-BOOK. 


cock  or  valve  is  necessary  on  the  water-supply.  The  jet  D  serves 
to  create  a  vacuum,  and  assists  in  carrying  the  water  forward 
against  the  boiler-pressure ;  and,  as  it  is  stationary,  it  is  always  in 
a  proper  position  to  produce  a  vacuum,  the  required  volume  of 
steam  necessary  to  force  the  water  into  the  boiler  being  obtaiuec^ 


by  moving  the  plug  B,  as  in  the  case  of  class  A.  To  lift  water 
from  a  well,  open  the  steam- valve  for  the  purpose  of  removing 
the  water  of  condensation ;  then  close  it ;  after  which  move  the 
plug  B  back  against  the  disc  of  the  jet  D ;  then  open  the  steam- 
valve,  and,  when  the  water  appears  at  the  overflow,  move  the  plug 
slowly  forward  until  the  water  ceases  flowing,  after  which  the  in- 
jector will  sometimes  lift  water,  but  are  said  not  to  be  reliable  as 
lifting  injectors. 

The  Eclipse  Injector. 

The  cut  on  page  425  represents  the  Eclipse  Injector,  with  Sellers' 
Lifting  Jet,  which  is  claimed  to  embody  many  desirable  features, 
such  as  simplicity,  durability,  and  easy  adjustment,  and  to  work 
under  a  steam-pressure  ranging  from  5  to  150  lbs.  per  square  inch, 
without  breaking  the  water-supply ;  that,  when  it  becomes  neces- 
sary to  fill  a  boiler  with  cold  water,  all  the  working  parts  may  be 
removed  from  the  barrel,  which  will  permit  the  water  to  flow 
through  without  obstruction  ;  that  it  will  heat  the  feed- water  up 


THE   ENG1NEER\s  HANDY-BOOK. 


426 


to  200°  Fall. ;  and  that  it  is  particularly  adapted  to  heatiug  the 
water  in  the  tenders  of  locomotives,  to  prevent  them  from  freezing. 

The  same  precautions  that  are  necessary  to  be  observed  in  con- 
necting all  injectors,  viz.,  that  the  steam  be  taken  from  the  high- 
est point  of  the  boiler ;  that  a  valve  must  be  placed  in  the  steam- 
pipe  near  the  swivel,  and  also  one  on  the  feed-pipe  between  th^ 
boiler  and  check-valve  ;  and  that  the  water  connections  are  per- 
fectly  tight,  are  applicable  to  this  one,  also. 

Directions  for  using  the  Eclipse  Injector. —  Close  the  regulator, 
A,  by  turning  it  to  the  right  as  far  as  it  will  move ;  then  turn  on 
the  steam,  slowly  at  first,  until  the  water  which  is  taken  up  shows 
at  the  overflow;  next  open  the  regulator  slowly,  untU  the  dis- 


charge from  the  overflow  ceases ;  the  injector  will  then  be  working. 
When  it  becomes  necessary  to  stop  working,  first  turn  off"  the 
steam ;  then  close  the  regulator,  as  otherwise,  when  started  again, 
it  will  not  lift  quickly ;  but,  when  the  water  flows  to  the  injector 
from  either  a  hydrant  or  tank,  after  the  injector  has  once  been 
adjusted,  it  is  only  necessary  to  turn  on  the  water,  and  then  the 
steam.  To  remove  the  working  parts  from  the  barrel  of  the  in- 
jector, screw  the  jam-nut,  C,  up  against  the  main  nut,  D ;  then,  by 
keeping  the  jam-nut  tight  against  Z>,  the  injector  may  be  easily 
drawn  out  from  the  shell.  Should  it  become  necessary  to  repack 
the  injector  at  M,  care  must  be  taken  to  insert  the  packing  \u 
front  of  the  follower,  T,  and  compress  it  with  the  latter. 
36* 


426  THE   ENGINEER'S  HANDY-BOOK. 

The  Clipper  Injector. 

The  annexed  cut  represents  the  Clipper  Adjustable  Injector, 
which  is  claimed  to  possess  the  following  good  qualities  :  simplicity 
of  construction,  certainty  of  action,  ease  of  starting,  non-liability  to 

get  out  of  order,  large  capacity,  and 
that  it  will  draw  water  as  far  as  a 
siphon  or  pump,  and  force  it  into 
the  boiler  under  ordinary  pressure. 
Besides,  it  can  be  regulated  so  as  to 
feed  one-half  its  capacity,  and  will 
not  slip. 

All  that  is  necessary  to  insure 
certainty  of  action  in  this  injector, 
is  to  place  it  in  a  horizontal  position, 
and  take  the  steam  from  the  highest 
point  in  the  boiler,  and  to  have  the 
steam-  and  water-pipes  fully  as  large 
as  the  openings  in  tlie  swivels  to 
which  they  are  attached. 

The  cut  on  page  427  shows  a  sec- 
tion of  Lynde  Clipper  Injector. — A 
is  the  shell  or  body ;  B,  the  steam- 
tube  ;  C,  the  jet  or  lifting-tube ;  i), 
the  water-tube ;  H,  the  swivel  which 
is  kept  from  turning  by  the  fins  H; 
Ky  the  bonnet,  by  unscrewing  which 
the  tubes  B  and  C  may  be  re- 
moved; M  and  N,  revolving  lever 
and  handle  by  which  to  regulate  tke 
water  and  steam  ;  0,  overflow  holes ; 
0\  holes  to  assist  in  lifting,  on  starting  the  injector ;  Qj  strainer 
to  prevent  any  foreign  substances  from  entering  the  injector  with 
the  water ;  R,  ribs  to  prevent  the  shell  from  springing ;  W,  over- 
flow valve  and  spring. 


THE   engineer's  HANDY-BOOK. 


427 


How  to  start  the  injector  when  the  water  flows  to  it. —  Draw  the 
steam-tube,  B,  nearly  all  the  way 
back,  by  revolving  the  handle,  M, 
which  actuates  tube,  B  (same  as  the 
wheel  does  the  valve  in  a  common 
globe-valve),  and  pull  lever,  M',  all 
the  way  back.  Open  steam-valve 
a  little,  to  clear  pipe  of  condensed 
water  ;  when  steam  blows  out  at 
overflow,  push  lever,  M\  full  for- 
ward, open  steam  full,  and  open 
water-cock.  When  water  runs  solid 
from  overflow,  draw  lever,  M\ 
slowly  all  the  way  back,  and  turn 
in  tube,  JS,  slowly  till  water  ceases. 
The  injector  is  then  set  to  feed  its 
maximum  amount  at  the  pressure 
of  steam  then  used.  It  may  then 
be  started  by  simply  opening  steam- 
valve  a  little,  as  above,  to  clear  the 
pipes ;  then  close  steam-  and  open 
water -cocks.  When  water  runs 
solid  at  overflow,  open  steam-valve 
slowly,  and  feeding  will  commence 
without  operating  lever.  If'. 

How  to  start  the  injector  when 
the  water  is  to  be  lifted. — Draw 
steam-tube,  B,  nearly  all  the  way 
back,  and  pull  lever,  M\  all  the 

way  back ;  open  steam-valve  a  little  (or  all  the  way,  if  desired), 
to  clear  steam-pipe,  and,  when  steam  appears  at  overflow,  push 
lever,  M\  full  forward  —  the  water-pipe  being  open,  water  will 
be  likely  to  appear  at  once  (or  in  a  few  seconds)  at  overflow ;  if 
not,  pull  lever,  M\  back  a  moment  to  clear  the  injector  and  push 
full  forward  again.    As  soon  as  the  water  runs  solid  at  overflow^ 


428 


THE   engineer's  HANDY-BOOK. 


pull  lever,  M\  slowly  all  the  way  back,  and  screw  in  tube,  JS,  until 
feeding  commences.  It  is  then  feeding  the  maximum  amount  at 
pressure.  It  may  then  be  started  by  turning  on  steam  ;  push  lever, 
M\  full  forward,  and  then  pull  back  as  above,  when  water  appears 
at  overflow. 

To  reduce  the  feed  in  either  case.  —  When  the  injector  is  set 
as  above,  push  lever,  M',  forward,  until  water  begins  to  run  from 
overflow  ;  then  cut  off*  water  with  handle,  M,  until  it  ceases  at 
overflow,  and  repeat  as  long  as  it  will  bear,  and  continue  to  feed. 
The  minimum  feed  is  thus  obtained,  and  the  water  is  delivered  to 
the  boiler  the  hottest. 

TABLE 


OF  CAPACITIES  OF  CLIPPER  INJECTORS. 


Pipes. 

Approximate  Gallons 

No. 

of  Water  thrown  per 

Hour,  with  60  to  100 

STEAM. 

WATER. 

Lbs.  of  Steam. 

1 

f  in. 

1  in. 

60  to  90 

2 

3  u 

i  " 

150  to  180 

3 

3  a 

4 

250  to  300 

4 

3  U 
4 

1  " 

500  to  600 

5 

•     1  " 

U  " 

700  to  900 

6 

1  " 

U  " 

800  to  1200 

7 

U  " 

U  " 

1200  to  1600 

8 

U  " 

U  " 

1600  to  2000 

9 

n " 

2  " 

2000  to  2500 

10 

U  " 

2  " 

2500  to  3000 

12 

2  " 

2\  " 

3000  to  3500 

There  is  one  principle  that  governs  the  action  of  all  injectors, 
which  is,  that  if  the  temperature  of  the  water  is  raised  too  high, 
they  will  not  w^ork.  Some  injectors  will  lift  water  as  high  as  20 
feet,  according  to  the  temperature  of  the  water  and  the  size  of  the 
injector ;  large  injectors  having  invariably  the  greatest  lifting  ca- 
pacity.   As  the  amount  of  water  thrown  depends  on  the  velocity 


THE   engineer's    FI  A  N  1)  Y  -  B  O  O  K  . 


429 


of  the  steam,  it  follows  that  the  volume  of  water  thrown  will  be 
much  greater  with  high  than  with  low  steam-pressure. 

The  annexed  cut  represents  Mack's  Fixed-Nozzle  Injector, 
which  is  said  to  have  a  working  range,  with  one  handle,  of  from 
15  lbs.  to  175  lbs.  steam-pressure  per  square  inch,  and  is  always 
reliable,  whether  worked  con- 
stantly or  once  in  a  year. 
When  extraordinarily  high 
pressure  is  required,  an  ex- 
tra valve  is  attached,  which 
will  admit  of  working  this 
injector  at  a  range  of  5  lbs. 
to  250  lbs.  per  square  inch. 

Fixed  -  Nozzle  Injectors 
have  no  movable  or  adjust- 
able parts  within  them  ;  they 
can  be  regulated  by  steam-  and 
water-supply  cocks  on  the 
outside  of  the  instruments ; 
but  there  is  one  pressure  of 
steam  to  which  they  have 
been  primarily  adapted,  and 
at  which  they  work  best,  viz., 
at  the  pressure  at  which  they 
give  the  largest  duty.  Inas- 
much as  the  pressure  of  steam 
in  stationary  boilers  is,  as  a 
rule,  held  constant,  they  are 
well  suited  for  that  kind  of 
work ;  but  in  cases  where  there 
is  a  great  variation  of  press- 
ure they  are  not  so  well  suited.  Mack's  Fixed-Nozzle  Injector. 
There  are  fewer  of  them  in  use  than  of  other  arrangements,  never- 
theless some  of  them  give  satisfaction,  but  in  any  case  their  sim- 
plicity is  their  chief  recommendation. 


430 


THE   ENGINEER'S  HANDY-BOOK. 


The  Inspirator. 

The  inspirator,  though  belonging  to  the  injector  family,  differs 
from  the  latter,  inasmuch  as  it  is  a  double  instrument,  consisting 

of  a  lifting  and  a  forcing 
side ;  the  latter  being  to  all 
intents  and  purposes,  with 
slight  mechanical  varia- 
tions, an  "  injector,"  while 
the  former  is  a  kind  of  a 
pump,  which  supplies  the 
forcer  side  with  water. 
The  whole  machine  is  a 
curious  combination  of 
mechanical  arrangements 
for  lifting  and  forcing 
water,  and  cannot  be  act- 
ually said  to  be  either  an 
injector  or  a  pump,  though 
it  performs  the  functions 
of  both.  The  inspirator 
is  capable  of  lifting  and 
forcing  water  or  other 
fluids  to  a  great  height. 
It  will  lift  water  25  feet, 
with  a  steam-pressure  of 
30  lbs.,  provided  the  suc- 
tion-pipe be  perfectly  tight, 
and  the  instrument  is  fur- 
nished with  dry  steam ;  but 
the  temperature  of  the 
water  will  control  to  a 
certain  extent  the  height 
of  the  lift.  For  a  lift  of  25  feet,  the  temperature  of  the  water 
should  not  exceed  100°  Fah. 


THE   ENGINEER\s  HANDY-BOOK. 


431 


STEAM 


Whenever  the  inspirator  fails  to  act,  the  trouble,  in  a  majority 
of  cases,  will  be  due  to  leakage  in  the  pipes.  Other  causes  are  due 
to  the  area  of  the  suction- 
pipe  being  too  small,  which 
ought  in  all  cases  to  be 
larger  than  the  nipple  or 
swivel  to  which  it  is  con- 
nected ;  but  in  any  case  it  is 
advisable  to  have  a  foot-or 
check-valve  in  the  suction- 
pipe,  below  the  level  of  the 
water  in  the  well,  river,  or 
mine. 

How  to  operate  the  in- 
spirator,—  When  steam  is 
admitted  to  the  inspirator, 
it  passes  through  the  lifter 
steam-jet,  leaps  the  interval, 
A,  through  the  combiniyig- 
tube,  and  escapes  at  the  over- 
flow, thus  expelling  the  air 
and  producing  a  partial 
vacuum,  into  which  the 
water  rises.  As  soon  as  the 
water  appears  at  the  over- 
flow, close  valve  No.  1,  to 
prevent  it  from  escaping, 
and  induce  it  to  pass  up  the 
forcer,  and  through  the  com- 
bining-tube  B ;  then  by  open- 
ing the  handle  No.  2,  and  closing  No.  3,  the  water  is  forced 
directly  through  the  feed-  or  delivery-pipe  into  the  boiler  or  tank, 
as  the  case  may  be.  The  inspirator  is  adapted  as  a  boiler-feeder 
for  either  stationary,  locomotive,  or  marine  engines. 


OVERFLOW. 


432  THE   ENGINEER'S  HANDY-BOOK. 


TABLE 

OP  CAPACITIES  OF  THE  HANCOCK  INSPIRATOR. 


Number  of  Inspi- 
rator. 

Size  of  Pipe  Con- 
nections. 

Gallons  per  Hour. 

1  n 

1- 

15 

320 

20 

1 

540 

25 

u 

900 

30 

li 

1260 

35 

li 

1540 

40 

2 

2240 

45 

2 

2820 

50 

2i 

3480 

Instructions  for  Setting  up,  Properly  Attaching,  and 
Adjusting  Injectors. 

All  pipes,  whether  steam,  water-supply,  or  delivery,  should  be 
of  the  same  internal  diameter  as  the  hole  in  the  corresponding 
branch  of  the  injector,  and  as  short  and  straight  as  practicable. 

When  floating  particles  of  wood,  or  other  matter,  are  liable  to 
be  in  the  supply-pipe,  a  strainer  should  be  placed  over  the  receiv- 
ing end  of  it.  The  holes  in  this  strainer  should  be  as  small  as  the 
smallest  opening  in  the  delivery-tube,  and  the  total  area  of  all 
the  holes  should  be  greater  than  the  area  of  the  water-supply  pipe, 
to  compensate  for  the  closing  of  some  of  them  by  deposits. 

The  steam  should  be  taken  from  the  highest  part  of  the  boiler, 
in  order  to  .avoid  the  carrying  over  of  water  with  the  steam ;  but 
it  should  not  be  taken  from  the  pipe  leading  to  the  engine,  unless 
such  pipe  is  large. 

When  any  injector  capable  of  raising  water  is  set,  care  must  be 
taken  to  have  the  pipes  as  tight  as  possible,  so  as  not  to  draw 
air. 


THE   engineer's  HANDY-BOOK. 


433 


If  the  water  is  not  lifted  by  the  injector,  but  flows  to  it  from  a 
tank  or  hydrant,  there  should  be  a  cock  in  the  water-supply  pipe ; 
and  in  case  the  injector  be  self-adjusting,  this  cock  should  be  of  a 
kind  that  will  prevent  any  considerable  pressure  in  the  water- 
supply  pipe  between  it  and  the  injector.  The  higher  the  steam 
is  carried  in  the  boiler,  the  greater  may  be  the  pressure  in  the 
water-supply  pipe. 

There  should  always  be  a  stop-valve  or  cock  in  the  steam-pipe, 
between  the  steam-space  in  the  boiler  and  the  injector,  and  a 
check-valve  between  the  water-space  of  the  boiler  and  the  in- 
jector. 

When  an  air-chamber  is  placed  below  the  injector  in  the  water- 
supply  pipe,  care  should  be  taken  to  keep  it  sr.:pplied  with  air. 
When  the  injector  lifts  water  from  a  tank  placed  below  it,  no  pre- 
caution is  needed,  as,  when  the  injector  is  stopped,  the  water  flows 
back  and  air  enters  the  pipe. 

When  fed  from  a  hydrant  through  a  self-regulating  valve,  there 
should  be  a  pet-cock  between  the  valve  and  the  air-chamber, 
which  will  serve  to  drain  away  the  water  when  the  valve  is  closed 
and  the  injector  is  not  working. 

After  all  the  pipes  are  properly  connected  to  the  injector  and  to 
the  boiler,  and  it  is  ready  for  work,  they  should  be  disconnected 
and  well,  washed  out,  in  order  to  remove  any  obstructions,  such  as 
paint,  red  lead,  straw,  or  shavings,  that  may  have  found  their  way 
into  them.  Many  excellent  instruments  have  been  condemned 
because  those  who  set  them  up  failed  to  take  this  precaution. 

Injectors,  like  pumps  and  other  hydraulic  machines,  are  not  so 
reliable  in  action  when  working  water  of  a  high  temperature  as 
when  the  temperature  is  moderate ;  though  there  are  several  in- 
jectors, owing  to  peculiarities  in  their  mechanical  arrangements, 
more  reliable  in  this  respect  than  others. 

Injectors,  like  nearly  all  other  machines  connected  with  steam- 
boilers,  are  frequently  neglected,  and  allowed  to  become  covered 
with  filth,  which,  in  view  of  their  wonderful  utility  and  efficiency, 
is  a  reproach  to  those  who  have  them  in  charge. 
37  2  (J 


434 


THE   ENGINEER'S  HANDY-BOOK. 


The  Ejector  or  Lifter. 


STEAM 


The  annexed  cut  represents  the  ejector  or  lifter,  which  is  prac- 
tically the  lifter  side  of  the  inspirator,  with  a  reduced  steam-jet 
and  enlarged  lifter  combining-tube.  It  is  suitable  for  breweries, 
tanneries,  bleacheries,  etc.;  for  trans- 
ferring large  volumes  of  water,  lye,  acid, 
and  other  liquids.  It  will  deliver  more 
fluid  of  any  kind  at  a  low  lift,  with  a 
lower  pressure  of  steam,  than  either  the 
injector  or  inspirator;  but  it  is  not  as 
reliable,  or  as  well  adapted  to  the  dif- 
ferent purposes  for  which  these  instru- 
ments are  used,  as  either  of  them.  It 
answers  a  very  good  purpose  when  cellars 
become  flooded  in  consequence  of  heavy 
rain-falls,  high  tides,  or  overflowing  of 
culverts,  and  requires  no  very  intelligent 
management.  Its  action  is  based  on  the 
I  DELIVERY  same  principle  as  that  of  the  injector, 
and  is  more  simple,  as  it  has  no  adjust- 
able or  movable  parts. 

Method  of  starting  the  ejector. — All 
that  is  necessary  to  start  the  ejector  is  to 
turn  on  the  steam,  after  which  it  will 
work  as  long  as  the  water-supply  and 
steam-pressure  continue ;  and  it  is  imma- 
terial what  lift  it  is  started  on,  as  the 
steam-supply  may  be  gradually  reduced 
to  meet  the  requirements  of  the  quantity  of  water  to  be  dis- 
charged. If  started  on  a  steam-pressure  of  40  lbs.  per  square 
inch,  it  will  continue  to  work  until  the  pressure  falls  to  15 
pounds. 

The  Ejector  and  Inspirator  are  manufactured  by  the  Hancock 
Inspirator  Co.,  Boston,  Mass. 


SUCTION 


THE   engineer's  HA>"DY-B00K. 


435 


Jamison's  Steam  Water-Ejector. 

The  annexed  cut  represents  Jamison's  steam  water-ejector, 

as  it  is  termed,  which,  like  other  eject- 
ors, is  suitable  in  tanneries,  breweries, 
or  places  where  large  quantities  of  liq- 
uids which  contain  floating  particles, 
such  as  malt,  hops,  bark,  sawdust,  etc., 
require  to  be  lifted,  as  it  has  no  moving 
mechanism  to  be  obstructed  or  clogged. 
Its  action  is  based  on  the  same  prin- 
ciple as  the  steam  siphon,  and  when 
once  started,  by  simply  turning  on  the 
steam,  it  will  continue  to  work  as  long 
as  the  steam  and  water-supply  lasts, 
through  a  diminution  of  pressure  rang- 
ing from  15  to  100  lbs.  per  square  inch, 
and  irice  versa.  As  they  are  generally 
made  of  brass  or  some  non-corrosive 
metal,  they  rarely  ever  wear  out  or 
require  any  attention.  They  are  just 
as  eflScient  when  submerged  in  water 
or  other  liquid  as  when  directly  on 
the  surface. 

TABLE 

OF  CAPACITIES  OF  JAMISON's  STEAM  WATER-EJECTOR. 


SIZE. 

I  inch  ejector. 


CAPACITY. 

4  gals,  per  minute. 
8 


1 

U 
li 
2 

3 


12 
15 
20 
30 
80 
300 


436         THE  engineer's  handy-book. 


Questions, 

THE  ANSWERS  TO  WHICH  WILL  BE  FOUND  IN  THE  TEXT. 

What  is  the  object  of  attaching  a  condenser  to  a  steam-engine? 

Give  the  names,  and  the  advantages  and  disadvantages  of  the 
two  kinds  of  condensers  in  most  general  use,  with  a  description 
of  the  same. 

Explain  how  the  injection -water  enters  and  escapes  from  surface 
and  jet  condensers. 

State  what  relative  proportion  the  jet  condenser  should  bear  to 
the  steam-cylinder  of  a  condensing  engine. 

State  what  relative  proportion  the  cooling  surface  in  a  surface 
condenser  should  bear  to  the  cubic  contents  of  the  steam-cyl- 
inder. 

State  the  respective  advantages  and  disadvantages  of  having 
condensers  too  large  or  too  small. 

What  is  the  most  advantageous  temperature  at  which  to  keep 
the  water  in  hot  wells  ?  and  what  effect  does  too  high  or  too  low  a 
temperature  exert  on  the  economical  working  of  the  engine  ? 

Explain  the  arrangements  by  which  the  bilge  injection- water  is 
introduced  into  jet  and  surface  condensers. 

What  would  be  the  effect  of  not  shutting  off  the  injection- water 
when  the  engine  is  stopped  ? 

State  the  quantity  of  water  necessary  to  condense  steam,  with 
a  formula. 

Give  the  rule  for  finding  the  cooling  surface  in  the  tubes  of  sur- 
face condensers. 


THE   ENGINEER'S    HANDY-BOOK.  437 

What  is  the  most  practicable  method  of  cleaning  the  tubes  of 
surface  condensers  when  they  become  foul  ? 

State  what  relative  proportions  the  circulating-pump  should 
bear  to  the  steam-cylinder  of  a  surface-condensing  engine. 

Explain  the  principles  involved  in  the  working  of  the  Korting 
jet  condenser  ;  also  the  method  of  starting  it. 

What  is  the  meaning  of  the  term  vacuum  ? 

How  is  the  vacuum  maintained  in  the  condenser  of  a  condens- 
ing engine  ? 

What  effect  has  the  temperature  of  the  injection-water  on  the 
vacuum? 

How  is  the  vacuum  measured  ? 

Suppose  the  steam-gauge  shows  60  lbs.  pressure,  and  the 
vacuum-gauge  registers  26  inches,  what  will  be  the  effective  press- 
ure on  the  piston? 

Why  does  the  condensation  of  steam*  produce  a  vacuum  in  the 
condenser  ? 

How  is  the  state  of  the  vacuum  shown? 

From  what  causes  is  an  imperfect  vacuum  most  likely  to  arise? 

How  would  you  proceed  to  discover  the  cause  of  an  imperfect 
vacuum  ? 

Is  a  vacuum  power? 

Can  a  perfect  vacuum  be  maintained  ?    If  not,  why  not  ? 

What  is  the  object  of  air-pumps  used  in  connection  with  con- 
densing engines  ? 

What  relative  proportion  should  the  air-pump  bear  to  the  steam- 
cylinders  of  simple  and  compound  surface-condensing  engines  ? 
37* 


438         THE  engineer's  handy-book. 

What  relative  proportions  should  the  air-pump  bear  to  the 
steam-cylinders  of  jet-condensing  engines  ? 

What  is  the  difference  in  the  duty  which  the  air-pumps  of  sur- 
face-condensing and  jet-condensing  engines  have  to  perform? 

Explain  the  difference  between  bucket,  piston,  plunger,~single 
and  double  acting  air-pumps. 

What  is  the  object  of  attaching  an  air-valve  to  a  circulating, 
reciprocating,  or  double  acting  pump  ? 

What  is  the  most  probable  cause  of  an  air-pump  with  a  foul 
valve,  and  no  discharge-valve,  failing  to  work  ? 

*What  is  the  object  of  an  air-pump  trunk? 

What  are  the  functions  of  an  air-pump  pet-cock? 

Describe  the  construction  of  an  air-pump  bucket. 

With  what  metals  are  air-pump  rods  generally  covered,  and 
why  are  they  so  covered  ? 

Give  the  shape  and  functions  of  a  ship's  side  air-pump  discharge- 
valve. 

What  is  the  object  of  an  air-casing  ? 

What  is  the  object  of  the  mariner's  compass? 

What  are  the  causes  of  variation  of  the  compass? 

What  is  the  meaning  of  the  term  rhumbs  ? 

What  is  the  equator? 

What  are  the  poles? 

What  is  a  meridian? 


THE    engineer's    HANDY- BOOK.  439 

What  is  the  meaning  of  the  term  latitude? 

What  is  understood  by  difference  of  latitude? 

What  Is  the  meaning  of  the  term  departure  in  its  relation  to 
navigation? 

What  is  the  meaning  of  the  term  longitude? 

What  are  degrees  of  longitude? 

Give  the  rule  for  reducing  degrees  of  longitude  to  time. 

What  is  the  difTerence  of  longitude  between  any  two  places? 

Define  the  term  distance  in  its  relation  to  navigation. 

Define  the  terms  course  and  magnetic  course  as  applied  to 
navigation  ;  also  the  terms  true  course  and  course  made  good. 

Define  the  terms  variation,  deviation,  and  error  of  the  compass. 

Define  the  term  leeway. 

Define  the  terms  meridian ;  and  also  apparent,  observed,  and 
true  altitude. 

Explain  the  term  visible  horizon  and  dip  of  the  horizon. 
What  is  the  meaning  of  the  term  refraction? 
Give  the  meaning  of  the  term  port  side. 
What  is  the  parallax? 

What  is  the  meaning  of  the  term  declination? 
What  is  meant  by  polar  distance  ? 
What  is  meant  by  right  ascension? 
What  is  meant  by  semi-diameter? 


440  THE  engineer's  handy-book. 

Give  the  meaning  of  the  term  starboard  side. 
What  is  meant  by  the  augmentation  of  the  moon's  semi-diameter 
What  is  the  zenith  distance? 

Explain  the  terms  civil,  astronomical,  sidereal,  apparent,  and 
mean  time ;  also  the  equation  of  time. 

What  is  meant  by  the  hour-angle  of  a  celestial  object? 

Define  the  terms  ecliptic  and  the  tropics. 

Define  the  term  azimuth. 

What  is  meant  by  the  term  amplitude  when  applied  to  naviga- 
tion and  astronomy  ? 

What  is  the  meaning  of  the  term  dead  reckoning? 

Give  the  saih'ng  distance  from  New  York,  in  geographical  miles, 
to  different  ports. 

Give  the  latitude  and  longitude  of  different  seaports. 

To  what  class  of  machines  do  pumps  belong  ? 

What  principle  is  involved  in  the  working  of  all  pumps? 

How  high  will  an  ordinary  pump,  in  good  condition,  lift  water 
or  other  liquids  ? 

What  condition  limits  the  action  of  all  atmospheric  pumps? 

Give  the  rule  for  finding  the  size  of  pump-plunger  and  stroke 
for  an  engine  of  any  given  power. 

Give  the  rule  for  finding  the  quantity  of  water,  or  other  liquid, 
that  any  pump  will  lift  or  discharge  in  a  given  time. 

Give  the  most  probable  causes  why  pumps  fail  to  work  satis- 
factorily. 


THE   ENGINEER'S   HANDY-BOOK.  441 

Explain  the  difference  between  lift-force,  single-acting,  and 
double-acting  pumps. 

What  is  the  meaning  of  the  term  circulating-pump? 

What  is  the  object  of  placing  an  air-chamber  on  a  pump  ? 

Give  the  pule  for  finding  the  power  required  to  raise  a  given 
quantity  of  water. 

Give  the  reason  why  pumps  will  not  lift  very  hot  water. 

What  is  the  object  of  placing  a  pet-cock  on  the  barrel  of  a 
feed-pump  ? 

What  is  the  object  of  placing  mud-boxes  or  strainers  on  the 
suction-pipes  of  pumps  ? 

What  course  would  you  adopt  to  prevent  pump-pipes  from 
freezing  in  cold  weather  ? 

Explain  the  meaning  of  the  terms  injector  and  ejector  when 
applied  to  hydraulic  machines. 

Explain  the  principles  involved  in  the  working  of  the  injector. 

What  conditions  limit  the  height  to  which  injectors  can  lift  water? 

Under  what  three  heads  may  all  injectors  be  classed? 

What  are  the  meanings  of  the  terms  maximum  and  minimum 
delivery  ? 

What  is  the  meaning  of  the  term  range  when  applied  to  injectors? 

To  what  class  of  machines  does  the  inspirator  belong  ? 

On  what  principle  is  the  action  of  the  inspirator  based? 

Explain  the  advantages  and  disadvantages  of  injectors,  ejectors, 
and  inspirators  over  pumps. 


442  THE   ENGINEER'S    H  A  NB  Y -BOOK: . 


PART  SIXTH. 


Steam-Boilers. 

Steam-boilers  embrace  a  great  variety  of  designs;*  in  fact, 
any  vessel  in  which  steam  is  generated  for  mechanical  purposes 


may  be  termed  a  steam-boiler,  regardfess  of  shape  or  form.  The 

*  For  a  full  description  of  all  the  steam-boilers  in  use  at  the  present  day, 
their  peculiarities  of  design,  construction,  care,  and  management^  see  Roper's 
"  Use  and  Abuse  of  the  Steam-Boiler»!i 


THE   ENGINEER'S  HANDY-BOOK. 


443 


most  common  forms  of  marine-boilers  in  use  at  the  present  clay 
are  the  horizontal  and  vertical,  fire-  and  water-tubulars.  The  water- 
tubular  is  fast  disappearing,  and  is  now  rarely  to  be  found  except 
in  the  United  States  Navy,  or  those  of  other  countries.  Its  gradual 
disappearance  arises  from  the  fact  that  it  is  more  expensive  to  build 
and  to  repair,  is  more  dangerous,  and  requires  extra  care  and  man- 
agement. If  a  tube  splits  or  becomes  leaky  in  the  fire-tubular  boiler, 
the  diflSculty  may  be  met  by  plugging,  and  the  vessel  can  proceed 
on  its  way ;  but  if  the  same  accident  occur  in  a  water-tubular,  it 
would  be  necessary  to  blow  out  the  boiler.  The  same  principle  which 
was  embodied  in  the  Montgomery  water-tubular  marine-boiler  was 


Fire-Tubular  Marine-Boiler. 


introduced  into  the  Dimpfel  locomotive-boiler,  but  soon  fell  int© 
disuse  in  both  cases.   The  fire-box,  fire-tubular  marine-boiler,  with 


444 


THE   ENGINEER'S  HANDY-BOOK. 


combustion-chamber  at  the  back  end  and  superheater  in  the  up- 
take, is  the  type  of  boiler  most  generally  in  use  on  the  steamships 
of  the  different  lines  sailing  out  from  the  seaports  of  this  country 
as  well  as  those  of  other  nations. 

Aside  from  the  choice  among  engineers  between  the  two  forms, 
there  is  a  wider  difference  in  their  proportion  than  in  anything 
else  connected  with  the  steam-engine.  While  all  generally  agree 
that,  in  proportioning  a  marine-boiler,  there  should  be  sufficient 
grate-surface  to  consume  the  maximum  quantity  of  coal  required 
for  the  engine  for  which  that  boiler  was  intended  to  furnish  steam, 
and  that  there  should  be  sufficient  heating-surface  to  absorb  the 
heat  evolved  by  the  fuel ;  yet,  when  it  comes  to  laying  down  pro- 
portions, one  engineer  allows  twice  as  many  square  feet  of  heat- 
ing-surface to  one  square  foot  of  grate-surface  as  another.  Watt's 
proportions  for  land-  and  marine-boilers  varied  from  9*5  to  10  feet 
of  heating-surface  to  1  square  foot  of  grate-surface.  Maudsley 
and  Miller  allowed  10  square  feet  of  heating-surface  to  1  square 
foot  of  grate-surface  in  the  boilers  of  the  celebrated  ocean  steamer 
Great  Western,  and  from  10  to  12  square  feet  of  heating-surface 
to  1  square  foot  of  grate-surface  in  other  marine-boilers  that  they 
constructed  about  the  same  time ;  so  that  neither  they  nor  Watt 
seemed  to  have  any  fixed  rule,  nor  did  there  appear  to  be  any 
among  naval  constructors  either  in  this  country  or  England. 

This  may  be  seen  from  the  fact  that  the  U.  S.  gun-boat  Massa- 
chusetts had  34  feet  of  heating-surface  to  1  square  foot  of  grate- 
surface,  while  the  Vixen,  with  the  same-sized  engine,  had  only  16  to  1. 
The  merchant-steamer  Constitution  had  66  square  feet  of  heating- 
surface  to  one  square  foot  of  grate-surface,  while  the  Franklin,  a 
steamship  of  nearly  the  same  capacity,  with  engines  of  the  same 
power,  had  only  28  to  1.  The  boilers  of  the  celebrated  steamships 
of  the  Collins  Line,  which  have  made  such  fast  time  between 
New  York  and  Liverpool,  had  33  square  feet  of  heating-surface 
to  1  square  foot  of  grate-surface,  while  in  the  boilers  of  the  steam- 
ships of  the  Cunard  Line  the  heating-surface  varies  from  18  to  37 
square  feet  to  1  square  foot  of  grate-surface.    The  Mary  Powell, 


THE   ENGINEER\s    HANDY-BOOK.  445 

one  of  the  fastest  river-boats  in  American  waters,  has  17  square 
feet  of  heating-surface  to  1  square  foot  of  grate-surface.  In  pro- 
portioning the  heating-surface  to  the  cubic  contents  of  tlie  cylinder, 
the  same  variation  seems  to  exist  which  shows  there  is  no  recognized 
proportion  for  either.  The  steamship  Massachusetts,  U.  S.  N.,  has 
77  square  feet  of  heating-surface  to  1  cubic  foot  of  cylinder,  while 
the  Powhatan  has  less  than  15  square  feet,  and  the  San  Jacinto  has 
a  trifle  over  12.  The  merchant-steamer  Union  had  one  hundred 
and  eighteen  square  feet  of  heating-surface  to  1  cubic  foot  of 
cylinder,  while  the  Isaac  Newton  had  only  10  to  1.  The  steam-tug 
Rescue  had  63  square  feet  of  heating-surface  to  1  cubic  foot  of 
cylinder,  while  the  Anglo-Saxon  had  only  10  to  1. 

The  average  proportion  of  heating-surface  to  grate-surface  of 
345  steamships,  tugs,  and  ferry-boats  examined  was  about  30 
square  feet  of  heating-surface  to  1  square  foot  of  grate-surface, 
while  an  examination  of  a  great  number  of  steamships,  tug,  and 
ferry-boats  in  this  country,  England,  and  France,  showed  that  the 
average  proportion  of  heating-surface  to  1  cubic  foot  of  cylinder 
was  about  28.  In  stationary  boilers  the  heating-surface  varies 
from  12  to  30  to  1  square  foot  of  grate-surface,  while  in  some 
patented  sectional  boilers  there  are  60  to  70  square  feet  of  heat- 
ing-surface to  one  square  foot  of  grate-surface,  the  average  for 
locomotive-boilers  being  about  60  square  feet  of  heating-surface 
to  1  square  foot  of  grate-surface. 

To  proportion  a  marine-boiler  understandingly,  it  is  necessary 
to  know  the  size  of  the  engine  and  of  the  boat  or  ship,  the  load 
to  be  propelled,  and  the  speed  at  which  it  is  to  move.  The  engi- 
neer can  determine  the  pressure  and  volume  of  steam  required, 
and  decide  on  the  degree  of  expansion,  the  quantity  of  grate-  and 
heating-surface,  and  in  relation  to  these  two  latter  conditions,  as 
shown  in  the  foregoing  paragraphs,  the  field  has  a  very  wide  lati- 
tude. But  he  must  be  sure  that  the  boiler  possesses  sufficient 
strength  to  resist  in  safety  the  maximum  pressure  to  which  it  will 
ever  be  exposed ;  that  it  contains  sufficient  grate-surface  for  the 
combustion  of  the  necessary  quantity  of  fuel  under  any  circum- 
38 


446  THE   ENGINEER'S  HANDY-BOOK. 

stances ;  that  it  has  sufficient  heating-surface  to  evaporate  the  nec- 
essary quantity  of  water ;  that  it  is  capable  of  containing  a  suffi- 
cient supply  of  water  and  steam  to  prevent  undue  fluctuation, 
and  that  it  affords  convenient  facilities  for  the  repair  or  renewal 
of  any  of  its  parts.  After  the  foregoing  conditions  are  determined 
on,  another  object  of  great  importance  to  be  considered  is  making 
the  boiler  as  light  and  compact  as  possible.  The  term  heating- 
surface,  when  applied  to  steam-boilers,  means  all  that  part  of  the 
fire-box,  crown-sheet,  tube-sheets,  and  flues  with  which  the  fire  and 
flame  come  in  contact  in  their  escape  from  the  furnace  to  the 

chimney. 

Martin's  upright 
tubular- boiler  is 
sometimes  used  for 
marine  purposes. 
Its  only  advantage 
is  economy  of  space ; 
its  first  cost  is  more 
than  that  of  the 
ordinary  horizon- 
tal marine  tubular- 
boiler,  and  it  is  not 
more  efficient.  The 
capacity  of  the 
steam-room  is  about 
one-third  the  capac- 
ity of  the  boiler. 

The  quantity  of 
steam  that  can  be 
generated  in  any 
boiler  in  a  given 
time  is  dependent 
upon  a  great  varie- 
Direct  Flue  and  Return  Tubular  Marine-Boiler.  circumstances, 

such  as  the  kind  of  boiler,  its  condition  as  to  dirt,  scale,  etc.,  the 


THE   engineer's  HANDY-BOOK. 


447 


manner  in  which  it  is  set  and  fired,  the  quality  of  the  fuel  used, 
quantity  of  grate-surface,  amount  of  heating-surface,  draught, 
etc.,  while  the  amount  of  water  used  will  depend  entirely  on  the 
engine,  provided  the  steam  is  dry.  The  evaporation  in  tubular 
boilers, —  stationary,  locomotive,  and  marine, —  under  good  con- 
dition*, is  about  8^  to  9  lbs.  of  water  to  1  lb.  of  coal ;  in  flue- 
boilers,  6  to  7 ;  but  the  average  result  is  about  25  per  cent,  below 
this.  The  nominal  loss  of  fuel  in  boilers  is  rarely  less  than  30 
per  cent.,  and  is  frequently  as  high  as  50.  Taking  the  lowest 
estimate  at  30  per  cent.,  it  may  be  illustrated  as  follows :  The 
amount  necessary  to  produce  a  draught,  including  the  flame  which 
escapes  into  the  chimney,  20  per  cent. ;  particles  of  coal  falling 
through  the  grates,  5  per  cent. ;  loss  arising  from  the  formation  of 
carbonic  oxide,  3  per  cent.;  loss  induced  by  radiation,  2  per  cent. 

The  common  estimate  of  the  quantity  of  water  necessary  to 
produce  one  horse-power  is  one  cubic  foot;  the  amount  of  heating- 
surface  necessary  to  evaporate  one  cubic  foot  of  water  in  an  hour 
has  been  found,  by  experiment,  to  be  about  14  square  feet  to  J 
square  foot  of  grate-surface,  under  the  most  favorable  conditions. 
It  has  grown  into  a  custom,  in  estimating  the  horse-power  of  steam- 
boilers,  to  allow  14  square  feet  of  heating-surface  to  i  square  foot 
of  grate-surface;  but  the  evaporative  performance  of  steam-boilers 
varies  very  much,  as  in  one  boiler  a  cubic  foot  of  water  may  be 
evaporated  in  an  hour  by  9  square  feet  of  heating-surface  to  i 
square  foot  of  grate-surface,  while  another  will  take  double  the 
amount.  In  locomotives,  the  proportion  of  heating-surface  to 
grate-surface  is  about  50  to  1 ;  in  marine-boilers,  about  28  to  1 ; 
ordinary  cylinder-boilers,  about  15  to  1 ;  flue-boilers,  18  to  1 ; 
tubular-boilers,  from  20  to  24  to  1 ;  and  in  sectional-  or  patent- 
boilers,  about  30  to  1. 

The  tendency  of  water  to  foam  in  marine-boilers  is  frequently 
attributed  to  the  presence  of  dirt,  or  other  saline  matter,  in  the 
water ;  but  it  is  often  induced  by  want  of  proper  relations  between 
the  heating-surface,  steam-room,  and  water-space  of  the  boiler,  as, 
when  the  discharge  of  steam  is  out  of  proportion  to  the  steam-room 


448 


THE   ENGINEER'S  HANDY-BOOK. 


in  the  boiler,  the  high  temperature  required  to  generate  steam  with 
sufficient  rapidity  to  supply  the  demand  causes  violent  boiling,  and 
the  agitation  is  greater  when  the  relation  between  the  temperature 
and  pressure  is  most  disturbed.  This  is  often  the  case  with 
tug-boats  just  starting  to  tow  a  heavy  vessel.  Boilers  with  a 
large  amount  of  heating-surface  and  small  steam-room  gei^rally 
foam. 

Marine-boilers  are  generally  surmounted  by  a  dome,  and, 
though  domes  do  not  add  much  to  the  cubical  capacity  of  the 
steam-room,  they  have  the  effect  of  superheating  the  steam,  or 
imparting  to  it  an  extra  heat,  which  greatly  increases  its  expan- 
sive force,  and  renders  it  less  liable  to  condense  in  the  passages 
between  the  boiler  and  the  cylinder. 

Fittings  of  marine-boilers. —  The  fittings  of  marine-boilers  are 
the  funnels,  air-casings,  uptakes,  smoke-box  and  fire-doors,  grate- 
bars,  bearers  and  bridges,  main  steam-pipe  and  stop-valve,  donkey- 
valve,  safety-valves  and  drain-pipes,  main-  and  donkey-feed  check- 
valves,  blow-off-  and  scum-cocks,  water-gauges,  test  water-cock, 
steam-valves  for  whistle,  and  winches. 

Bursting  Pressure  of  Cylindrical  Steam-Boilers. 

The  force  which  will  rupture  a  cylindrical  boiler  depends  upon 
the  diameter  and  the  pressure  of  the  steam  ;  hence,  the  total  press- 
ure to  be  sustained  is  equal  to  the  diameter,  multiplied  by  the 
pressure  per  square  inch  of  surface,  multiplied  by  the  length  of 
the  boiler.  The  shorter  the  tube,  and  the  smaller  the  diameter, 
the  greater  its  power  of  resistance,  and  vice  versa.  No  matter 
what  the  diameter  of  a  boiler  may  be,  the  transverse,  or  cross 
pressure  tending  to  tear  it  asunder,  will  always  be  double  the 
longitudinal  pressure. 

Rule  for  finding  the  bursting  pressure  of  cylindrical  boilers  with 
riveted  seams. 

Multiply  the  tensile  strength  of  the  iron  (which  should  be  taken 
at  50,000  lbs.  per  square  inch  of  section)  by '56,  if  single  riveted, 
38-^ 


THE   ENGINEEr\s  irANOY-ROOK. 


449 


and  by  '70,  if  double  riveted,  and  divide  by  the  diameter  of  the 
boiler,  multiplied  by  the  number  of  pieces  of  metal,  that  would 
make  one  square  inch  of  cross  section  ;  the  product  wUl  be  the 
bursting  strain. 

For  instance,  what  pressure  will  it  require  to  rupture  a  cyl- 
indrical boiler  with  riveted  seams,  diameter  12  inches,  thickness 
of  iron  i  inch  ? 

^^^?o^^  ^^  =  583-33  X  2  =  1166-66  lbs.,  about  one-fifth  of 
12  X  4 

which  would  be  the  safe  working-pressure. 

Rule /or  finding  the  strain  exerted  in  a  longitudinal  direction  by 
the  pressure  of  steam  in  a  boiler. 

Multiply  the  area  of  the  head  by  the  pressure  in  pounds  per 
square  inch,  and  divide  the  product  by  the  circumference  of  the 
boiler,  and  by  the  number  of  thicknesses  of  iron  that  would 
make  one  square  inch  of  cross  section  ;  the  quotient  will  be  the 
strain. 

Example.  Diameter,  12  inches.  Area,  113*09  square  inches. 
Pressure,  11661  lbs. 

^^^37'69  ^^^4  ~  ^^^^^  P^^  square  inch  of  sectional  area 
in  a  longitudinal  direction. 

Rule  for  finding  the  strain  exerted  in  a  transverse  direction  by 
the  pressure  of  steam  in  a  boiler. 

Multiply  the  pressure  per  square  inch  by  the  diameter,  and  also 

by  the  number  of  thicknesses  of  metal  it  will  take  to  make  one 

square  inch  of  cross  section,  and  divide  the  product  by  2,  because 

the  boiler  has  2  sides. 

-        ,      1166-66  x  12  x  4      oiooQQi  Ik  •  u 

Example.  =  31999*84  lbs.  per  square  inch 

of  sectional  area  in  a  transverse  direction. 

The  power  of  any  steam-boiler  to  resist  strain  depends  upon 
the  thickness  and  quality  of  material,  character  of  the  workman- 
ship, and  the  shape  of  the  parts  subjected  to  strain. 
38*  2D 


450 


THE   ENGINEER'S  HANDY-BOOK. 


The  above  cut  represents  the  arrangements  most  generally  em- 
ployed for  bracing  marine  steam-boilers,  and  includes  the  vertical 
and  horizontal,  angle,  toggle,  dome,  and  crown  braces ;  as  well  as 
the  buckles,  crow-feet,  angle-irons,  girths,  stay-bolts,  and  leg  braces. 
The  tubes  'answer  for  braces  for  the  tube-sheets ;  the  crow-feet  for 
the  crown  and  dome;  the  proper  strength  for  the  braces  of  marine- 
boilers  may  be  found  by  multiplying  the  number  of  square  inches 
exposed  to  the  pressure  of  the  steam  by  six  times  the  steam-press- 
ure to  be  carried. 


THE   ENGINEER'S  HANDY-BOOK. 


451 


Rules. 

Rule  for  finding  the  safe  working-pressure  of  iron  boilers.  —  Multi- 
ply the  thickness  of  iron  by  '56,*  if  single  riveted,  and  '70,  if 
double  riveted  ;  multiply  this  product  by  10,000  (safe  load) ;  then 
divide  this  last  product  by  the  external  radius  (less  thickness  of 
iron) ;  the  quotient  will  be  the  safe  working-pressure  in  pounds 
per  square  inch,  which,  if  multiplied  by  5,  would  give  the  burst- 
ing pressure. 

In  the  foregoing  rule,  the  tensile  strength  of  the  iron  is  taken 
at  50,000,  as  it  has  been  repeatedly  proved  by  experiment  that 
boiler-plate  possesses  less  tenacity  than  the  same  iron  would  have 
if  rolled  into  bars. 

Rule  for  finding  the  internal  strain  to  which  boilers  are  subjected 
when  under  pressure,  —  Multiply  the  surface  of  the  plate  required 
for  one  square  inch  of  sectional  area  by  the  pressure  of  steam  in 
lbs.  per  square  inch ;  multiply  this  result  by  the  diameter  of  the 
boiler  in  inches,  and  divide  by  2,  which  gives  the  strain  per  square 
inch  of  sectional  area  to  which  the  boiler  is  subjected. 

The  surface  of  boiler-plate  required  for  one  square  inch  of 
sectional  area  will  depend  upon  the  thickness  of  plate ;  thus,  iron 
i  inch  thick  will  require  4  superficial  inches  to  make  one  square 
inch  of  sectional  area;  iron  \  inch  thick  will  require  2,  and  so  on. 

Rule  for  finding  the  pressure  per  square  inch  of  sectional  area  on 
the  crown-sheets  of  steam-boilers.  —  3Iultiply  the  width  of  the  crown- 
sheet  in  inches  by  its  length  in  inches ;  multiply  this  product  by 
the  pressure  of  the  steam  in  lbs.  per  square  inch  by  the  gauge ; 
divide  by  2,  if  i  inch  iron,  and  so  on  according  to  the  thickness. 

Rule  for  finding  the  aggregate  strain  caused  by  the  pressure  of 
steam  on  the  shells  of  boilers.  —  Multiply  the  circumference  in  inches 
by  the  length  in  inches ;  midtiply  that  product  by  the  pressure  in 
pounds  per  square  inch.  The  result  will  be  the  aggregate  pressure 
on  the  shell  of  the  boiler.   

^  Multiplied  by  '56,  because  the  iron  loses  44  per  cent,  of  its  strength  in  tlie 
process  of  punching.  Double-riveted  seams  equal  '70  of  the  original  strength. 


452 


THE   ENGINEER'S  HANBY-BOOK. 


Rule  for  finding  the  safe  external  pressure  on  boiler-fiues,  — Multi- 
ply the  square  of  the  thickness  of  the  iron  by  the  constant  whole 
number  806,300 ;  divide  this  product  by  the  diameter  of  the  flues  in 
inches;  divide  the  quotient  by  the  length  of  the  flue  in  feet;  divide 
this  quotient  by  3:  the  result  will  be  the  safe  working-pressure. 

Ru\e  for  finding  the  collapsing  pressure  of  boiler  fiues,  —  Multiply 
the  square  of  the  thickness  of  the  iron,  in  thirty  seconds  of  an 
inch,  by  the  constant  number  262*4 ;  divide  this  product  by  the 
length  of  the  flue  in  feet ;  divide  this  quotient  by  the  diameter  of 
the  flue  in  quarter  feet,  and  the  quotient  will  be  the  collapsing 
pressure  in  pounds  per  square  inch. 

Rule /or  finding  the  number  of  square  feet  of  heating-surface  in  a 
tube,  or  any  number  of  tubes. 

Multiply  the  circumference  of  the  tube  in  inches  by  its  length 
in  inches,  and  divide  by  144 ;  the  quotient  will  be  the  number  of 
square  feet  of  heating-surface.  This,  multiplied  by  the  whole  num- 
ber of  tubes,  will  give  the  aggregate  amount  of  heating-surface. 

Rule  for  fiyiding  the  strength  of  single-  or  double-riveted  seams. 

Multiply  the  area  of  the  metal  between  the  holes,  in  square 
inches,  by  the  ultimate  strength  of  the  metal  after  punching  the 
holes.  The  product  will  be  the  strength  of  the  seam.  Single-riv- 
eted seams  being  equal  to  about  56  per  cent,  of  the  original 
strength,  and  double-riveted,  70  per  cent. 

Rule  for  finding  the  strain  due  to  the  pressure  of  the  steam  on 
boiler-stays. 

Multiply  the  area  in  inches  between  the  stays  by  the  pressure 
in  pounds  per  square  inch.  The  product  will  be  the  strain  in 
pounds  per  square  inch. 

Rules. 

Rwie  for  finding  the  heating-surface  of  fire-box  boilers — locomotive, 
marine,  or  stationary.  —  Multiply  the  length  of  the  furnace-plates 
in  inches  by  their  height  above  the  grate  in  inches ;  multiply  the 
width  of  the  ends  in  inches  by  their  height  in  inches ;  .multiply 
the  length  of  the  crown-sheet  in  inches  by  its  width  in  inches ; 


THE    engineer's  HANDY-BOOK. 


453 


also  the  combiued  circumference  of  all  the  tubes  in  inches  by  their 
length  in  inches;  from  the  sum  of  these  four  products  subtract  the 
combined  area  of  all  the  tubes  and  the  fire-door  ;  divide  the  re- 
mainder by  144,  and  the  quotient  will  be  the  number  of  square 
feet  of  heating-surface. 

Rule  for  flue-boilers.  —  Multiply  |  of  the  circumference  of  the 
shell  in  inches  by  its  length  in  inches ;  multiply  the  combined 
circumference  of  all  the  flues  in  inches  by  their  length  in  inches ; 
divide  the  sum  of  these  two  products  by  144,  and  the  quotient 
will  be  the  number  of  square  feet  of  heating-surface. 

Rule  for  cylinder-boilers. — Multiply!  of  the  circumference 
of  the  shell  in  inches  by  its  length  in  inches,  divide  by  144,  and 
the  quotient  will  be  the  number  of  square  feet  of  heating-surface. 

Rule  for  tubular-boilers,  —  Multiply  |  of  the  circumference  of 
the  shell  in  inches  by  its  length  in  inches ;  multiply  the  combined 
circumference  of  all  the  tubes  in  inches  by  their  length  in  inches. 
To  the  sum  of  these  two  products  add  |  the  area  of  both  tube- 
sheets;  from  this  sum  subtract  the  combined  area  of  all  the  tubes; 
divide  the  remainder  by  144,  and  the  quotient  will  be  the  number 
of  square  feet  of  heating-surface. 

Rule  for  finding  the  heating-surface  of  vertical  tubular  boilers,  such 
as  are  generally  used  for  fire-engines.  —  Multiply  the  circumference 
of  the  fire-box  in  inches  by  its  height  above  the  grate  in  inches. 
Multiply  the  combined  circumference  of  all  the  tubes  in  inches 
by  their  length  in  inches,  and  to  these  two  products  add  the  area 
of  the  lower  tube-  or  crown-sheet,  and  from  this  sum  subtract  the 
area  of  all  the  tubes,  and  divide  by  144.  The  quotient  will  be 
the  number  of  square  feet  of  heating-surface  in  the  boiler. 

Boiler-Stays. 

Boiler- stays,  in  any  case,  are  but  substitutes  for  real  strength 
in  the  shell  or  other  parts  of  the  boiler.  The'  strain  usually  al- 
lowed on  them  per  square  inch  is  about  5000  lbs.  The  most 
common  method  of  securing  them  is  to  cut  a  thread  on  both  ends, 


454 


THE   engineer's  HANDY-BOOK. 


and  screw  and  cold-rivet  them  into  the  plates ;  another  method 
is  to  flatten  the  ends  of  the  stay,  and  secure  them  to  the  boiler 
by  means  of  one  or  two  rivets;  still  another  is  to  rivet  eye-bolts 
into  the  shell  of  the  boiler,  fork  the  end  of  the  stay-bolt,  and 
attach  to  the  eye-bolt  by  means  of  a  cotter.  But  all  the  forego- 
ing methods  have  their  objections,  as,  when  the  stays  become 
slack,  and  it  becomes  necessary  to  make  them  taut,  the  necessity 
of  cutting  away  the  rivets,  destroying  the  thread,  and  weakening 
the  boiler  is  necessarily  involved. 

The  most  modern  and  permanent  method  of  securing  stays  to 
the  shell  or  ends  of  steam-boilers  is  by  riveting  angle-irons  to 
the  parts  to  be  braced,  as  shown  at  a,  a,  a,  a,  in  the  cut  on  page 
450,  and  drilling  holes  in  the  angle-irons  where  the  brace  is  to  be 
attached.  Then  the  rods  may  be  forked,  and  attached  to  the 
angle-irons  by  means  of  a  cotter,  which  term  means  a  blank  bolt, 
with  a  splint  in  its  end,  which  may  be  expanded  with  a  cold-chisel, 
to  prevent  them  from  coming  out.  This  arrangement  has  this 
advantage,  that,  where  the  braces  become  slack,  they  may  be 
made  taut  by  taking  them  out,  heating  them  in  a  forge,  and  up- 
setting them.  The  value  of  stays  as  a  substitute  for  strength  and 
safety  depends  very  materially  not  only  on  the  manner  in  which 
they  are  attached  to  the  parts  they  are  intended  to  strengthen, 
but  also  on  their  position,  which  affects  their  ability  to  stand  ten- 
sile strain  and  compression-pressure.  If  the  stay  is  properly 
anchored,  it  will  stand,  on  a  straight  pull,  a  resistance  equal  to  its 
tensile  strength,  or  it  will  resist  the  force  of  compression  equal  to 
its  crushing  strength ;  but  if  it  stands  slightly  oblique,  its  power 
of  resistance  will  be  very  much  diminished. 

Stay-Bolts. 

Stay-bolts  are  the  means  usually  employed  to  strengthen  the 
flat  surfaces  in  the  fire-box  and  water-legs  of  locomotives  and 
marine-boilers ;  they  are  generally  screwed  into  both  plates,  on 
each  side  of  the  water  space,  and  riveted  by  the  process  called 


THE   ENGINEER'S    HANDY-BOOK.  455 

cold  riveting.  Numerous  ordinary-sized  bolts  are  preferable  to  a 
few  large  ones.  The  difficulty  in  the  case  of  stay-bolts  does  not 
arise  ordinarily  from  tensile  strength,  brought  upon  the  bolt  by 
the  steam-pressure,  but  from  relative  changes  in  position  of  the 
two  sheets  through  which  the  bolt  passes,  caused  by  a  difference 
in  the  temperature  of  the  two  sheets,  and  the  consequent  difference 
in  expansion.  For  instance,  if  the  side  sheet  of  a  fire-box  of  a 
locomotive-  or  marine-boiler  expands  in  a  vertical  direction  i  of 
an  inch  more  than  the  outside  sheet,  then  all  bolts  in  the  top  row 
will  have  their  inner  ends  forced  upwards  from  their  original 
position  to  that  extent,  and  the  boilers  must  spring  or  bend  ac- 
cordingly ;  whereas,  when  both  sheets  become  again  of  the  same 
temperature,  the  ends  of  the  bolts  are  drawn  back  to  their  original 
position. 

TABLE 

SHOWING  THE  BREAKING  STRAIN  OF  IRON  AND  COPPER  STAY-BOLTS. 


Breaking 
Weight  in 
Pounds. 

Strength 
distributed 

over  25 
inches  area 
would  give 

Lbs.  per 
square  inch. 

Strength 
distributed 

over  16 
inches  area 
would  give 

Lbs.  per 
square  inch. 

1.  Iron  into  iron  screwed  and  ) 

2.  Iron  into  copper  screwed  ) 

3.  Iron  into  copper  screwed  ) 
only  .  ^  1 

4.  Copper  into  copper  screw- ) 
ed  and  riveted  .    ...  j 

25,000 
21,400 
16,200 
14,400 

1,000 

856 
648 
576 

1,563 
1,338 
1,013 
900 

Scale  in  Steam-Boilers. 

Marine-boilers  using  sea-water  require  to  be  frequently  blown 
out  to  prevent  incrustation,  or  deposit  of  salt,  on  their  heating 


456 


THE   ENGINEER'S  HANDY-BOOK. 


surfaces,  which  lie  between  the  iron  and  the  water.  It  not  only 
causes  an  increased  consumption  of  coal,  but  allows  the  iron  to 
become  crystallized  and  burned.  The  evil  effects  of  the  scale  are 
due  to  the  fact  that  it  is  a  non-conductor  of  heat.  Its  conducting 
power,  compared  with  that  of  iron,  is  as  1  to  35*5.  Consequently, 
more  fuel  is  required  to  heat  water  in  an  incrusted  boiler  than  in 
the  same  boiler  if  clean.  A  scale  inch  thick  will  require  the 
extra  expenditure  of  15  per  cent,  more  fuel ;  this  ratio  increases 
as  the  scale  thickens.  Thus,  when  it  is  i  inch  thick,  60  per  cent, 
more  fuel  is  needed ;  J  inch  thick,  150  per  cent.,  and  so  on ;  con- 
sequently, to  raise  water  in  a  boiler  to  any  given  heat,  the  fire-sur- 
face of  the  boiler  must  be  heated  to  a  temperature  in  accordance 
with  the  thickness  of  the  scale. 

To  raise  steam  to  a  pressure  of  ninety  pounds,  the  water  must 
be  heated  to  about  320°  Fah.  In  a  clean  boiler  of  |  inch  iron, 
this  may  be  done  by  heating  the  external  surface  of  the  shell  to 
about  325°.  If  ^  inch  of  scale  intervenes  between  the  shell  and 
the  water,  such  is  its  non-conducting  power,  that  it  will  be  neces- 
sary to  heat  the  fire-surface  to  about  700°,  almost  red  heat.  Now^ 
the  higher  the  temperature  at  which  iron  is  kept,  the  more  rapidly 
it  oxidizes,  and  at  any  heat  above  600°  it  very  soon  becomes  gran- 
ular and  brittle,  and  is  liable  to  bulge,  crack,  or  otherwise  give 
way  to  the  internal  pressure.  This  condition  predisposes  the  boiler 
to  explosions,  and  makes  necessary  expensive  repairs.  Again,  it  is 
readily  seen  that  the  presence  of  scale  renders  slower  and  more 
difficult -the  raising,  maintaining,  and  lowering  of  s.team. 

The  principal  ingredient  in  the  scale  which  forms  in  marine- 
boilers  using  sea-water  is  sulphate  of  lime,  but  no  very  injurious 
effect  will  take  place  in  boilers  if  the  degree  of  sal tn ess  is  not 
allowed  to  exceed  In  fact,  a  thin  coat  of  scale  is  beneficial,  as 
it  protects  the  iron  from  corrosion  and  internal  grooving. 

Lord's  Boiler  Compound  appears  to  be  the  only  chemical  prep- 
aration in  use  at  the  present  day  that  will  prevent  the  formation 
of  scale,  or  remove  it  after  it  has  been  formed,  in  any  class  of 
boilers,  whether  stationary,  locomotive,  or  marine,  as  it  neutral- 


THE   ENGINEEK'S  HANDY-HOOK. 


457 


izes  the  action  of  the  natural  chemical  salts  which  form  the 
basis  of  all  scale  and  incrustation. 

An  analysis  of  sea-water  shows  the  relative  quantities  of  the 
ingredients  it  contains. 


Water 

Cliloride  of  Sodium  . 
Chloride  of  Potassium 
Chloride  of  Magnesium 
Bromide  of  Magnesium 
Sulphate  of  Magnesia 
Sulphate  of  Lime 
Carbonate  of  Lime  . 


964-745 
27-059 
0-766 
3-666 

0-  029 
2-296 

1-  406 
0-033 


constitute  the  basis  of  the  scale  which 
using  fresh-water  from  wells,  lakes,  or 


The  minerals  which 

forms  in  steam-boilers 
rivers,  are  sulphate  of  lime,  phosphate  of  lime,  carbonate  of  lime, 
magnesia,  silica,  and  alumina,  with  small  quantities  of  sesquioxide 
of  iron,  baryta,  carbonic  acid,  organic  matter,  chlorine,  sulphuric 
acid,  potassa,  calcium,  soda,  phosphoric  acid,  magnesium,  etc. 
The  remedies  for  the  prevention  and  removal  of  scale  from  steam- 
boilers  are  almost  innumerable. 


Foaming  in  Marine-Boilers. 

Foaming  in  marine-boilers  using  jet-condensers  is  generally 
caused  by  changing  the  water  from  salt  to  fresh,  or  vice  versdj  and 
is  made  evident  by  the  boiling  up  of  the  water  in  the  glass  gauge. 
When  foaming  arises  from  this. cause,  the  water  in  the  boiler  should 
be  changed  as  soon  as  possible,  which  can  be  done  by  putting  on  a 
strong  feed,  and  blowing  out  continuously,  or  at  short  intervals ; 
it  may  even  become  necessary  to  throttle  down  the  engine,  cut  f  ff 
short,  or  even  stop,  in  order  to  ascertain  the  level  of  the  water  in 
the  boilers. 

Violent  foaming  can  be  checked  by  opening  the  furnace-door, 
closing  the  damper,  and  covering  the  fire  with  fresh  coal ;  but  this 
39 


458 


THE   engineer's  HANDY-BOOK. 


means  of  relief  should  be  used  as  little  as  possible,  because  it  has  a 
tendency  to  injure  the  boiler,  owing  to  the  sudden  contraction  of  the 
parts  most  exposed  to  the  fire.  All  the  phenomena  connected  with 
foaming  have  not  yet  been  satisfactorily  explained;  but,  from 
w^hatever  cause  it  may  arise,  it  is  always  attended  with  a  certain 
amount  of  danger.  Foaming  is  sometimes  confounded  with  ^nm- 
ingy  but  they  arise  from  different  causes,  and  are  productive  of  dif- 
ferent results.  Foaming  is  always  made  manifest  by  the  violent 
agitation,  the  rising  and  falling  of  the  water  in  the  gauge,  and 
the  muddy  appearance  of  the  water. 

Foaming  is  induced  in  stationary  boilers  by  a  filthy  condition, 
particularly  in  those  to  which  the  feed-water  is  supplied  through 
open  heaters,  in  consequence  of  the  oil  or  tallow  employed  for 
lubricating  the  cylinder  being  carried  over  with  the  exhaust- 
steam.  The  water  in  locomotive-boilers  foams  on  some  parts  of 
the  road,  while  on  other  sections  this  phenomenon  never  mani- 
fests itself,  which  may  be  attributed  to  the  presence  of  alkali  or 
saline  matter  in  the  water  with  which  the  boilers  are  supplied  on 
certain  parts  of  the  road.  Foaming  is  induced  in  all  boilers  by 
the  want  of  proper  proportion  between  the  water-space,  heating- 
surface,  and  steam-room  of  the  boiler,  and  also  from  the  absence 
of  sufficient  steam-room  in  the  boiler  to  supply  the  cylinder. 

Priming. 

The  term  Priming  is  understood  by  engineers  to  mean  the 
passage  of  water  from  the  boiler  to  the  steam-cylinder  in  the 
shape  of  spray  instead  of  vapor.  It  may  go  on  unseen,  but  it  is 
generally  made  manifest  by  the  white  appearance  of  the  steam 
as  it  issues  from  the  exhaust-pipe ;  as  saturated  steam,  or  steam 
containing  water,  has  a  white  appearance,  and  descends  in  the 
shape  of  mist ;  while  dry  steam  has  a  bluish  color,  and  floats  away 
in  the  atmosphere.  Priming  also  makes  itself  known  by  a  click- 
ing in  the  cylinder,  which  is  caused  by  the  piston  striking  the 
water  against  the  cylinder-head  at  each  end  of  the  stroke. 

Priming  is  generally  induced  by  a  want  of  sufficient  steam-room 


THE   ENGINEER'S   HANDY-BOOK.  459 


in  the  boiler,  the  water  being  carried  too  high,  or  the  steam-pi})e 
being  too  small  for  the  cylinder,  which  would  cause  the  steam  in 
the  boiler  to  rush  out  so  rapidly  that,  every  time  the  valve 
opened,  it  would  induce  a  disturbance,  and  cause  the  water  to  rush 
over  into  the  cylinder  with  the  steam. 

The  following  table  shows  the  result  of  a  series  of  experiments, 
carried  out  by  Captain  Rodman,  for  the  purpose  of  demonstrating 
the  effects  of  sudden  strains  on  wrought-iron,  a  bar  one  inch 
square,  of  the  best  quality  of  iron,  being  selected  for  the  purpose. 


Amount  of  Strain. 

Temp'y  Stretch. 
Tinnr  inch. 

Permanent  Stretch. 
iWiJ  of  ^"  inch. 

5,000  lbs  

20 

0 

10,000  "   

41 

1 

15,000  "   

57 

1 

20,000  "   

76 

3 

25,000  "   

100 

7 

30,000  "   

537 

408 

35,000  "   

1833 

1661 

40,000  "   

4000 

45,000  "  broke  

It  will  be  seen  from  the  above  table  that  the  first  essay,  by 
means  of  a  strain  of  5000  lbs.,  produced  no  permanent  stretch  in 
the  bar;  and  that  10,000  lbs.  and  15,000  lbs.,  respectively,  only 
produced  a  permanent  stretch  of  yVA  inch,  or  about  of 

the  temporary  stretch.  But  in  the  next  two  strains  of  20,000  and 
25,000  lbs.,  the  iron  begins  to  shows  a  great  acceleration  of  the 
weakening  process  or  increase  of  fatigue,  as  the  permanent  strain 
has  sprung  up  to  of  the  entire  stretch.  In  the  next  two  items 
this  acceleration  is  astounding,  the  permanent  stretch  being  |  of 
the  whole  upon  30,000  lbs,  and  -f^  of  the  permanent  stretch  of 
35,000  lbs.  The  tensile  strength  of  good  boiler-iron  increases  with 
an  increase  of  temperature  up  to  about  500°  Fah.,  consequently, 
a  steam-boiler  is  safer  and  stronger  under  a  moderately  high  steam- 
pressure  than  it  would  be  under  the  same  hydraulic  pressure. 


460  THE   ENGINEER'S  HANDY-BOOK. 

Deterioration  of  steam-boilers. — Deterioration  of  steam-boilers 
arises  from  the  following  causes:  want  of  lamination  in  the  sheets; 
overstretching  of  the  fibre  of  the  plate  in  the  process  of  rolling ; 
injuries  done  the  plate  in  the  process  of  punching ;  damage  in- 
duced by  the  use  of  the  drift-pin  ;  injury  done  the  plates  by  a 
want  of  skill  in  the  use  of  the  hammer,  or  in  the  processes  of 
hand-riveting  and  calking.  Other  causes  are  unequal  expan- 
sion and  contraction,  resulting  from  a  want  of  skill  in  setting  ; 
grooving  in  the  vicinity  of  the  seams;  internal  and  external 
corrosion ;  blowing  out  the  boiler  when  under  a  high  pressure, 
and  filling  it  again  with  cold  water  when  hot ;  allowing  the  fire  to 
burn  too  rapidly  after  starting,  when  the  boiler  is  cold ;  ignorance 
of  the  use  of  the  pick  in  the  process  of  scaling  and  cleaning ;  in- 
capacity of  the  safety-valve ;  excessive  firing ;  urging  or  taxing 
the  boiler  beyond  its  safe  and  easy  working  capacity ;  allowing 
the  water  to  become  low,  thus  causing  undue  expansion ;  deposits 
of  scale  accumulating  on  the  parts  exposed  to  the  direct  action  of 
the  fire,  thereby  burning  or  crystallizing  the  sheets  or  shell ;  and 
wuGting  of  the  material  by  leakage,  etc. 

Corrosion,  and  its  Analogy  to  Combustion.* 

The  term  corrosion  means  wasting,  pitting,  or  grooving  of  the 
material,  and  is  generally  referred  to  under  two  heads,  namely,  in- 
ternal and  external. 

Internal  corrosion  presents  itself  in  various  forms,  and  is  due  to 
various  causes,  but  principally  to  the  minerals  and  acids  con- 
tained in  the  feed-water  with  which  steam-boilers  are  supplied. 

External  corrosion  is  said  to  be  due  to  the  galvanic  action  of 
the  mineral  in  the  fuel  and  the  gases  in  the  atmosphere,  and  both 
are  intimately  associated  with  combustion,  or  stimulated  by  it ;  as 
the  acids  and  minerals  which  are  in  solution  in  the  water,  and  lib- 
erated by  the  heat,  attack  the  boiler  internally;  whilst  the  sulphur 
which  is  liberated  by  the  combustion  of  coal  has  a  strong  aflSnity 


^  See  Koper's  "  Use  and  Abuse  of  Steam-Boilers." 


THE   E  N  G  I  N  K  E  R  \S    H  A  N  I)  Y  -  R  ()  O  K  . 


461 


for  the  irou  of  which  boilers  are  constructed,  and  attack  it  ex- 
ternally. 

Manuiil  and  Mechanical  Firing. 

The  term  firing  is  understood  to  be  the  art  of  applying  fresh 
coal  or  other  fuel  to  a  furnace,  which  operation,  in  the  case  of  large 
furnaces,  incurs  the  severest  kind  of  manual  labor,  and  is  attended 
with  a  great  loss  of  fuel,  in  consequence  of  the 'great  volume  of 
cold  air  that  enters  the  furnace  every  time  the  operation  of  replen- 
ishing or  cleaning  the  fires  is  performed.  Numerous  attempts 
have  been  made  to  obviate  this  waste  by  the  invention  of  ma- 
chinery that  would  fire  or  supply  the  fuel  continuously,  but  so  far 
no  mechanical  arrangements  Have  proved  a  success ;  nor  is  it  at  all 
likely  that  they  ever  will,  as  there  are  difficulties  to  be  encountered 
which  no  human  ingenuity  in  the  design  of  machines  can  prob- 
ably ever  overcome.  It  is  impossible  to  design  a  machine  that 
will  distribute  the  coal  uniformly  over  the  surface  of  the  fire,  in- 
cluding the  sharp  corners,  etc.  Unless  that  can  be  done,  me- 
chanical firing,  however  ingenious  the  arrangement  may  be,  must 
ever  prove  a  failure. 

Even  if  a  machine  were  devised  that  would  distribute  the  fuel 
evenly  over  the  fire-surface,  it  would  not  be  available  for  cleaning 
the  fires,  and,  as  a  result,  there  would  be  nearly  the  same  loss  in- 
curred if  the  fires  have  to  be  cleaned  by  hand,  as  if  they  were  fed 
by  hand.  This  being  the  case,  the  question  would  naturally  be 
asked.  Why  is  it  that  thousands  of  dollars  have  been  expended  in 
attempts  to  fire  mechanically  ?  and  the  answer  would  be,  that  there 
are  always  parties  to  be  found  who  are  ready  to  devote  time  and 
invest  money  in  every  delusion  which  has  ever  been  promulgated 
in  connection  with  the  steam-engine  and  boiler.  If  fuel  could  be 
consumed  in  round  or  oval  furnaces,  it  would  render  more  service 
than  if  burned  in  square  furnaces,  as  there  is  always  more  or  less 
dead  material  in  the  square  confers  through  which  the  air  escapes, 
thus  lowering  the  temperature  in  the  furnace,  and  rendering  com- 
bustion less  active  and  more  wasteful. 
39* 


462 


THE   ENGINEER'S  HANDY-BOOK. 


Technical  Terms  applied  to  Firing. 

Start  Fires. — This  term  is  understood  to  mean  starting  fresh 
fires  in  furnaces  with  shavings,  wood,  coal,  etc. 

Bank  Fires.  — This  term  is  understood  to  mean  covering  the 
fires  down  with  a  thick  body  of  coal  at  night,  or  when  the  engine 
has  to  be  stopped  for  an  indefinite  period. 

Slice  Fires.  —  This  means  to  push  back  the  fire  to  the  bridge- 
wall,  and  then  draw  out  the  cinders,  after  which  the  fire  is  drawn 
forward,  distributed  over  the  grates,  and  fresh  fuel  supplied.  The 
terms  slice  and  clean  fires  have  the  same  meaning. 

Draw  Fires. — This  term  is  understood  to  mean  to  draw  the 
entire  fire  from  the  furnace  for  the  purpose  of  allowing  the  furnace 
to  cool  for  stoppage  or  repairs,  as  the  case  may  be. 

Technical  Terms  Employed  in  Relation  to  Boilers, 

Curvilinear  Seams.  —  The  curvilinear  seams  of  a  boiler  are 
those  around  the  circumference. 

Grate-Surface. — The  term  grate-surface  means  the  aggre- 
gate number  of  square  feet.  In  practice,  the  allowance  of 
grate-surface  is  about  three-fourths  of  a  square  foot  per  horse- 
power. 

Longitudinal  Seams. — The  seams  which  are  parallel  to  the 
length  of  a  boiler  are  called  the  longitudinal  seams. 

Safe-working  pressure,  or  safe  load.  —  The  safe-working  press- 
ure of  steam-boilers  is  generally  taken  as  ^  of  the  bursting  press- 
ure, whatever  that  may  be. 

Steam -Room.  — That  part  of  a  boiler  occupied  by  the  steam. 
In  practice,  it  is  about  i  of  the  cubic  contents  of  the  boiler. 

Water-Space.  — That  part  of  a  steam-boiler  which  is  occupied 
by  the  water.  It  is  generally  about  i  of  the  cubic  contents  of  the 
boiler. 

The  aggregate  space  in  all  classes  of  steam-boilers  may  be  em- 
braced under  two  heads,  viz.,  steam-room  and  water-space. 


THE   ENGINEEK's  HANDY-BOOK. 


463 


Friction  of  Riveted  Seams. 

Owing  to  the  contraction  of  rivets  in  cooling,  the  plates  are,  in 
many  instances,  brought  into  such  close  contact  that  the  friction 
between  them  is  sufficient  to  withstand  the  working  strain  without 
any  shearing  action  coming  upon  the  rivets.  This  is  more  especially 
the  case  with  machine  riveting.  The  contraction  of  a  wrought- 
iron  bar  in  cooling  is  nearly  equal  to  j-qI^^  of  its  length  for  a 
decrease  of  temperature  of  fifteen  degrees  Fah.,  and  the  strain 
thus  induced  is  about  one  ton  for  every  square  inch  of  sectional 
area  in  the  bar. 

Thus,  if  a  rivet  one  inch  in  section  were  closed  at  a  temperature 
of  900  degrees,  it  would  in  cooling  decrease  in  length  -i-^o%j^  of 
its  length ;  and  if  its  elasticity  and  strength  remained  perfect,  would 
produce  a  tension  of  60  tons.  The  ultimate  strength  of  rivet  iron, 
however,  being  only  24  tons,  the  rivet  would  in  cooling  be  per- 
manently elongated,  and  would  continue,  when  cool,  to  exert  a 
tension  of  24  tons,  providing  its  elasticity  remained  uninjured  by 
the  strain.  Thus,  if  the  rivets  were  not  in  contact  with  the  plates, 
excepting  at  the  head  and  tail,  the  plates  would  be  held  together 
by  a  pressure  of  24  tons,  and  this  friction  would  have  to  be  over- 
come before  the  rivet  came  into  action  as  a  mere  pin,  from  which 
will  be  seen  that,  by  judicious  riveting,  the  friction  may,  in  many 
cases,  be  nearly  sufficient  to  counterbalance  the  weakening  of  the 
plate  from  the  punching  of  the  holes. 

Calking. 

The  object  of  calking  is  to  bring  together  the  seams  of  boilers, 
tanks,  or  hulls  of  iron  vessels  after  riveting,  so  that  they  may  be 
perfectly  steam-  or  water-tight.  This  is  done  by  using  a  sharp 
tool  ground  to  a  slight  angle.  The  edge  of  the  plates  being  first 
chipped  or  planed  to  an  angle  of  about  110°,  the  calking-tool  is 
applied  to  the  lower  edge  of  the  chipped  or  planed  angle,  in  order 
to  drive  or  upset  the  edge,  thus  bringing  the  plates  together,  and 


464 


THE   engineer's  HANDY-BOOK. 


rendering  the  joint  to  all  appearances  perfectly  steam-tight,  and 
able  to  resist  the  internal  pressure  brought  to  bear  upon  this 
particular  point.  There  are  different  methods  of  calking,  but 
the  concave  method  has  many  points  of  preference  over  any 
other.  Boilers  should  never  be  calked  while  under  steam-  or  water- 
pressure,  however  light,  as  the  jarring  induced  by  the  calking  is 
liable  to  spring  the  seams  and  cause  fresh  leakage  in  other  parts 
of  the  boiler. 

Steam-Boiler  Explosions. 

The  principal  causes  of  explosions,*  in  fact,  the  only  causes, 
are  deficiency  of  strength  in  the  shell  or  other  parts  of  the  boilers, 
over-pressure  and  over-heating.  Deficiency  of  strength  in  steam- 
boilers  may  be  due  to  original  defects,  bad  workmanship,  deterio- 
ration from  use  or  mismanagement.  Deficiency  of  strength  aris- 
ing from  bad  workmanship  is  the  most  diflScult  to  discover,  and 
not  unfrequently  escapes  the  closest  scrutiny,  more  particularly  in 
the  case  of  flue,  tubular,  and  locomotive  boilers. 

Over- pressure  may  be  caused  by  the  safety-valve  being  over- 
weighted ;  by  its  sticking  on  its  seat ;  by  the  inadequate  size  of 
the  communication  between  the  boiler  and  valve,  or  by  an  incorrect 
and  worthless  steam-gauge.  The  same  effect  may  be  produced 
when  there  is  a  disproportion  between  the  grate-  and  heating-  sur- 
faces, or  where  the  heat  from  a  large  grate  is  concentrated  on  a 
small  space.  Under  such  circumstances,  the  heat  is  delivered  with 
such  intensity  as  to  lift  the  water  from  the  surface  of  the  iron, 
thereby  exposing  it  to  the  direct  action  of  the  fire. 

Explosions  occurring  from  excessive  firing  are  in  all  cases  the 
result  of  avarice,  ignorance,  or  a  want  of  skill  in  the  care  and 
management  of  the  steam-boiler.  Overheating  may  be  caused 
by  the  accumulation  of  hard,  solid  incrustation  adhering  to  the 
parts  most  exposed  to  the  direct  action  of  the  fire,  or  it  may  be 
due  to  insuflSciency  of  water,  resulting  from  leakage  of  the  valve 


*  See  Rop.er^s  "  Use  and  Abuse  of  the  Steam-Boiler." 


THE  enginp:kr\s  II and y- book. 


465 


or  stop-cock,  a  failure  in  the  supply-pipe,  or  a  neglect  to  turn  it 
on  at  the  proper  time  or  in  sufficient  quantity. 

A  steam-boiler  may  be  well  designed,  of  good  material,  and  of 
first-class  workmanship,  and  yet  in  a  few  months,  after  being  put 
under  steam,  it  may  explode  with  terrible  effect.  On  examining 
into  the  cause  of  the  explosion,  it  may  turn  out  that  the  water 
used  made  a  heavy  deposit ;  that  the  boiler  had  not  been  cleaned 
since  it  was  put  into  use ;  that  the  fires  had  been  fiercely  urged, 
and  the  water  driven  from  the  surface  of  the  iron ;  as  a  result, 
the  life  had  been  entirely  burned  out  of  the  sheets  over  and  around 
the  fire,  thereby  weakening  the  boiler,  and  putting  it  in  a  dan- 
gerous condition.  That  the  sudden  heating  or  cooling,  and  oxida- 
tion of  the  boiler,  induce  great  deterioration  of  strength  has 
been  proved  by  experience.  Defects  in  the  material,  as  blisters, 
lamination  arising  from  inferior  material,  or  want  of  care  in  the 
manufacture,  are  other  sources  of  weakness  in  steam-boilers. 

Safety- Valyes.* 

The  safety-valve  is  designed  on  the  assumption  that  it  will  rise 
from  its  seat  under  the  statical  pressure  in  the  boiler,  when  this 
pressure  exceeds  the  exterior  pressure  on  the  valve,  and  that  it 
will  remain  off  its  seat  sufBciently  far  to  permit  all  the  steam 
which  the  boiler  can  produce  to  escape  around  the  edges  of  the 
valve.  The  problem  then  to  be  solved  is :  What  amount  of  open- 
ing is  necessary  for  the  free  escape  of  steam  from  a  boiler  under  a 
given  pressure  ?  The  area  of  a  safety-valve  is  determined  from 
formulae  based  on  the  velocity  of  the  flow  of  steam  under  different 
pressures,  or  experiments  made  to  ascertain  the  area  necessary  for 
the  escape  of  all  the  steam  a  boiler  could  produce  under  a  given 
pressure.  But  as  valves  do  not  rise  appreciably  from  their  seats 
under  varying  pressures,  the  point  to  be  considered  is,  how  high 
any  safety-valve  will  rise  under  the  influence  of  a  given  pressure. 
This  question  cannot  be  determined  theoretically,  but  has  been 
settled  conclusively  by  Burg,  of  Vienna,  who  ascertained  from 


*  See  page  654. 


466  THE  engineer's  handy-book. 


careful  experiments  that  the  rise  of  the  valve  diminishes  rapidly 
as  the  pressure  increases,  as  may  be  seen  from  the  annexed  table. 


Pressure  in  Lbs. 

Rise  of  Valve. 

1 

Pressure  in  Lbs. 

Rise  of  Valve. 

12 
20 
35 
45 
50 

1 

36" 
45 
T4 

eV 
1 

56 

60 
70 
80 
90 

1 

Tg5 
1 

T65 

in  ordinary  safety-valves,  the  average  rise  for  pressures  ranging 
from  10  to  40  pounds  is  about  ^^j^  of  an  inch ;  from  40  to  70  pounds, 
about  -^Q,  and  from  70  to  90,  about  of  an  inch.  The  following 
table  gives  the  result  of  a  series  of  experiments  made  at  the  Nov- 
elty Iron  Works,  New  York,  some  years  ago,  for  the  purpose  of 
determining  the  exact  area  of  opening  necessary  for  safety-valves, 
per  each  square  foot  of  heating-surface,  at  different  boiler  press- 
ures. 


Boiler  Pressure 
in  Lbs.  Above 
the  Atmos- 
phere. 

Area  of  Orifice  in 
Sq.  In.  for  Each 
Sq.  Ft.  of  Heat- 
ing-Surface. 

Boiler  Pressure 
in  Lbs.  Above 
the  Atmos- 
phere. 

Area  of  Orifice  in 
Sq.  In.  for  Each 
Sq.  Ft.  of  Heat- 
ing-Surface. 

0-25 

•022794 

40- 

-001723 

0-5 

•021164 

50- 

•001389 

1- 

•018515 

GO- 

-001176 

2- 

•014814 

TO- 

-001015 

3- 

•012345 

80- 

-000892 

4- 

•010582 

90- 

-000796 

5- 

•009259 

100- 

-000719 

10- 

•005698 

150- 

-000481 

20- 

•003221 

200- 

•000364 

30- 

•002244 

Now,  if  we  compare  the  area  of  openings,  according  to  these 
experiments,  with  Zeuner's  formula,  which  is  entirely  theoretical, 


THE   ENGINEER\s  HANDY-BOOK 


467 


it  will  be  observed  that  the  results  from  the  two  sources  are  al- 
most identical. 

The  lift  of  safety-valves,  like  all  other  puppet-valves,  decreases 
as  the  pressure  increases ;  but  this  seeming  irregularity  may  be 
explained  as  follows  :  a  cubic  foot  of  water  generated  into  steam 
at  one  pound  pressure  per  square  inch  above  the  atmosphere  will 
have  a  volume  of  about  1600  cubic  feet.  Steam  at  this  pressure 
will  flow  into  the  atmosphere  with  a  velocity  of  482  feet  per  sec- 
ond. Now,  suppose  the  steam  was  generated  in  five  minutes,  or  in 
300  seconds,  and  the  area  of  an  orifice  to  permit  its  escape  as  fast 
as  it  is  generated  be  required,  1600  divided  by  482  X  300  will  give 
the  area  of  the  orifice,  1?-  square  inches.  If  the  same  quantity 
of  water  be  generated  into  steam,  at  a  pressure  of  50  pounds 
above  the  atmosphere,  it  will  possess  a  volume  of  440  cubic  feet, 
and  will  flow  into  the  atmosphere  with  a  velocity  of  1791  feet  per 
second.  The  area  of  an  orifice,  to  allow  this  steam  to  escape  in 
the  same  time  as  in  the  first  case,  may  be  found  by  dividing  440 
by  1791  X  300 ;  the  result  will  be  square  inches,  or  nearly  |  of 
a  square  inch,  the  area  required.  It  is  evident  from  this  that  a 
much  less  lift  of  the  same  valve  will  suflSce  to  discharge  the  same 
weight  of  steam  under  a  high  pressure  than  under  a  low  one,  be- 
cause the  steam,  under  a  high  pressure,  not  only  possesses  a  re- 
duced volume,  but  a  greatly  increased  velocity;  it  is  also  obvious 
that  a  safety-valve,  to  discharge  steam  as  fast  as  the  boiler  car 
generate  it,  should  be  proportioned  for  the  lowest  pressure. 

There  does  not  appear  to  be  any  recognized  rule  among  boilei 
makers  for  proportioning  safety-valves,  since,  while  one  allows  one 
inch  of  area  of  safety-valve  to  every  66  square  feet  of  heating- 
surface,  another  gives  1  inch  area  of  safety-valve  to  every  4  horse- 
power, while  a  third  allows  1  inch  area  of  safety-valve  to  1|  square 
feet  of  grate-surface.  This  last  proportion  has  been  proved  by 
experience  to  be  capable  of  admitting  of  a  free  escape  of  steam, 
without  allowing  any  greater  increase  of  pressure  than  that  for 
which  the  valve  is  loaded,  providing  that  all  the  parts  are  in  good 
working  order.    It  is  obvious,  that  no  valve  can  act  without  a 


468 


THE   engineer's  HANDY-BOOK. 


slight  increase  of  pressure,  as,  in  order  to  lift  at  all,  the  internal 
pressure  must  exceed  that  of  the  load.  Doubtless,  most  safety- 
valves  are  larger  than  is  actually  required,  and  but  few  boiler 
explosions  occur  from  want  of  safety-valve  area.  The  most  prob- 
able causes  of  accidents  arising  from  safety-valves  are  that  they 
are  either  overloaded  or  out  of  order.  A  badly  proportioned 
safety-valve,  whether  too  large  or  too  small,  is  objectionable,  and 
is  always  attended  with  a  certain  amount  of  danger. 

Rules. 

Rule  for  finding  the  weight  necessary  to  put  on  a  safety-valve  lever  y 
when  the  area  of  valve,  pressure,  etc.,  are  known,  —  Multiply  the 
area  of  valve  by  the  pressure  in  pounds  per  square  inch ;  multi- 
ply this  product  by  the  distance  of  the  valve  from  the  fulcrum  ; 
multiply  the  weight  of  the  lever  by  one-half  its  length  (or  its 
centre  of  gravity) ;  then  multiply  the  weight  of  valve  and  stem 
by  their  distance  from  the  fulcrum ;  add  these  last  two  products 
together;  subtract  their  sum  from  the  first  product,  and  divide 
the  remainder  by  the  length  of  the  lever ;  the  quotient  will  be  the 
weight  required. 

Rule  for  finding  the  pressure  per  square  inch  when  the  area  of 
valve,  weight  of  ball,  etc.,  are  known,  —  Multiply  the  weight  of  ball 
by  the  length  of  lever,  and  multiply  the  weight  of  lever  by  one- 
half  its  length  (or  its  centre  of  gravity)  ;  then  multiply  the  weight 
of  valve  and  stem  by  the  distance  from  fulcrum.  Add  these  three 
products  together.  This  sum  divided  by  the  product  of  the  area 
of  the  valve,  and  its  distance  from  the  fulcrum,  will  give  the  press- 
ure in  pounds  per  square  inch. 

Rule  for  finding  the  pressure  at  which  a  safety-valve  is  weighted 
when  the  length  of  lever,  weight  of  ball,  etc.,  are  known.  —  Multiply 
the  length  of  the  lever  in  inches  by  the  weight  of  the  ball  in 
pounds ;  then  multiply  the  area  of  valve  by  its  distance  from  the 
fulcrum ;  divide  the  former  product  by  the  latter ;  the  quotient 
will  be  the  pressure  in  pounds  per  square  inch. 


THE   ENGINEER'S  HANDY-BOOK. 


469 


Rule  for  finding  centre  of  gravity  of  taper- levers  for  safety-valves. 
—  Divide  the  length  of  lever  by  two  (2) ;  then  divide  the  length 
of  lever  by  six  (6) ;  and  multiply  the  latter  quotient  by  width  of 
large  end  of  lever,  less  the  width  of  small  end,  divided  by  width 
of  large  end  of  lever  plus  the  width  of  small  end.  Subtract  this 
product  from  the  first  quotient,  and  the  remainder  will  be  the  dis- 
tance in  inches  of  the  centre  of  gravity  from  large  end  of  lever. 

Dead-weight  safety-valves  are  those  in  which  a  pressure  is 
exerted  on  the  valve  by  means  of  a  weight  suspended  on  the  long 
arm  of  the  lever. 

Spring  safety-valves  are  those  in  which  the  pressure  of  the 
steam  against  the  face  of  the  valve  is  resisted  by  means  of  a  spiral 
spring.  They  are  generally  used  for  locomotives,  as,  in  consequence 
of  the  jar,  the  dead-weight  safety-valve  is  impracticable. 

Lock  safety-valves  are  those  in  which  the  weight  on  the  lever 
is  enclosed  in  a  lock-box,  to  prevent  the  engineer  from  increasing 
the  pressure  at  will.  This  arrangement  of  safety-valve  is  most 
generally  used  on  the  boilers  of  marine  engines,  tug-boats,  and 
ferries. 

Draught  in  Chimneys. 

The  presence  of  draught  in  any  locality  is  due,  to  a  certain  ex- 
tent, to  the  unbalanced  pressure  of  the  atmosphere,  and  is,  in 
many  cases,  intensified  and  heightened  by  natural  causes,  but 
more  frequently  by  mechanical  and  artificial  arrangements.  The 
natural  draught  or  rush  of  air  up  chimneys  or  funnels  is  caused  by 
the  buoyancy  both  of  the  rarefied  atmosphere  and  of  the  gases 
which  pass  through  the  fuel,  as  well  as  by  the  natural  affinity  of 
the  colder  and  denser  atmosphere  to  rush  in  and  fill  up  the  vacuum 
caused  by  the  escape  or  ascension  of  the  preceding  volume.  All 
the  phenomena  connected  with  draught  are  not  as  well  understood 
as  they  should  be,  considering  its  importance  as  an  agent  in  the 
promotion  and  maintenance  of  the  combustion  of  fuel ;  the  object 
of  draught  being  to  supply  oxygen  to  the-burning  fuel,  and  dissemi- 
nate or  eject  the  products  of  combustion. 
40 


470 


THE   engineer's  HANDY-BOOK. 


Numerous  attempts  have  been  made  at  different  times  to  laj 
down  rules  for  the  area  and  height  of  chimneys  that  would  produce 
sufficient  draught  for  the  consumption  of  a  certain  quantity  of 
fuel  in  a  given  time,  but  such  formulae  have  more  frequently  failed, 
than  succeeded,  in  giving  satisfactory  results,  which  is  due  prob- 
ably to  the  want  of  knowledge  of  the  requirements  in  each  in- 
dividual case,  and  of  the  location  and  surroundings.  Attempts 
are,  in  many  instances,  made  to  produce  a  good  draught  by  carry- 
ing the  chimney  above  all  surrounding  objects  and  buildings,  but  it 
frequently  occurs  that  shorter  chimneys  of  the  same  area  and 
internal  dimensions  have  a  better  draught.  It  is  claimed  by  some 
engineers  that  chimneys  ought  to  increase  in  area  from  bottom  to 
top,  to  be  capable  of  producing  a  good  draught,  while  others  assert 
just  ^the  reverse,  and  claim  that  they  ought  to  decrease  from  bottom 
to  top.  It  has  been  found  by  experiment  that  both  arrangements 
produced  a  good  draught  under  some  circumstances,  but  neither 
of  them  under  all  circumstances.  The  area  of  any  chimney  should 
increase  slightly  from  bottom  to  top,  in  order  to  provide  for  the 
increased  volume  of  the  heated  air  and  gases  resulting  from  their 
expansion.  It  has  been  found  that  round  flues  produced  a  better 
draught,  as  a  general  thing,  than  either  square  or  oval  ones  of  the 
same  area  and  height.  This  doubtless  arises  from  the  fact  that 
air,  rushing  through  or  up  a  flue  or  funnel,  has  a  tendency  to  as- 
sume the  form  of  a  screw,  which  is  due  probably  to  §ome  natural 
cause. 

Adverse  currents  and  capping  winds  frequently  interfere  with  the 
draught  in  short  chimneys,  but  the  same  effect  is  frequently  pro- 
duced on  tall  ones  during  some  kinds  of  weather  and  at  certain 
seasons  of  the  year ;  certain  it  is,  that  very  tall  stacks  do  not  pro- 
duce a  corresponding  draught  in  proportion  to  the  height,  and  it 
has  been  demonstrated  by  observation  that  there  is  nothing  to  be 
gained  by  raising  chimneys  very  high.  It  often  occurs  that  chim- 
neys of  apparently  sufficient  height  are  incapable  of  producing 
sufficient  draught.  This,  in  many  instances,  arises  from  the  fact 
that  the  quantity  of  fuel  consumed  in  the  furnace  will  not  produce 


THE   engineer's  HANDY-BOOK. 


471 


sufficient  heat  in  the  flue  to  rarefy  the  air  and  cause  draught,  while 
in  other  chimneys  of  ample  height  and  area,  in  consequence  of 
the  air  and  heated  gases  having  to  pass  through  a  long,  cold  flue 
between  the  boiler  and  chimney,  the  draught  is  sluggish  and  unsatis- 
factory. There  is  no  lack  of  formula?  for  proportioning  chimneys, 
which  have  been  furnished  by  Wye  Williams,  Rankine,  Weisbach, 
Trowbridge,  Steel,  Watt,  and  others,  but  each  is  only  applicable 
in  certain  cases ;  and  indeed  it  appears  that  Watt  knew  as  much 
about  proportioning  the  flue  as  any  of  our  modern  engineers, 
which  may  be  inferred  from  the  fact  that  modern  writers  on  the 
subject  refer  to  him  as  frequently  as  to  any  one  else.  This  goes 
to  show  that  we  have  not  made  such  rapid  advances  in  mechanical 
science,  so  far  as  regards  proportioning  chimneys  to  produce  good 
draught  under  all  circumstances,  as  might  have  been  expected,  con- 
sidering the  intelligence  of  the  present  generation  and  the  pro- 
gressive ingenuity  of  the  age. 

There  are  always  individuals  to  be  found  who  can  tell  how  to 
proportion  a  chimney  or  a  flue  that  will  produce  a  draught  sufficient 
to  carry  off*  the  smoke  and  waste  gases  resulting  from  the  con- 
sumption of  a  certain  quantity  of  fuel,  but  they  rarely  ever  ex- 
plain all  the  conditions  under  which  this  may  be  accomplished ; 
such  as  the  distance  between  the  furnace  and  chimney ;  whether 
the  flue  is  perfectly  straight,  or  contains  a  number  of  bends ;  and 
whether  in  its  course  it  ascends  or  descends.  Such  information 
is  akin  to  that  which  tells  engineers  that  a  pound  of  coal  will 
evaporate  8*or  9  lbs.  of  water,  but  never  gives  the  conditions  under 
which  it  may  be  done,  which  include  the  type  or  design  of  boiler, 
the  quality  of  the  iron,  the  condition  of  the  boiler  for  cleanliness, 
etc.,  the  purity  of  the  fuel,  and  the  intelligence  and  experience 
of  the  care  and  management.  It  is  well  known  to  most  experienced 
engineers  that  the  boiler  that  w^ill  evaporate  9  lbs.  of  water  per 
lb.  of  coal  under  some  circumstances,  will  not  evaporate  over  5 
lbs.  of  water  per  lb.  of  coal  under  others,  and  the  results  will  be 
about  the  same  in  regard  to  draught. 

A  forced  draught  may  be  produced  by  various  mechanical  ar* 


472 


THE   engineer's  HANDY-BOOK. 


rangements,  such  as  blowing-engines,  fan-blowers,  steam-jets,  etc. ; 
but,  although  it  may  be  suitable,  and  even  au  absolute  necessity 
in  the  prosecution  of  many  branches  of  mechanical  industries,  a 
forced  draught  is  objectionable  in  assisting  the  combustion  of  fuel 
for  the  generation  of  steam  in  ordinary  steam-boilers,  and  never 
fails  to  induce  mischievous  effects,  and  consequently  a  good  natural 
draught  is  very  much  to  be  preferred  when  attainable.  Any  flue 
ought  to  be  as  smooth  on  the  inside  as  circumstances  will  permit, 
in  order  to  diminish  the  friction  between  the  walls  of  the  flue  and 
the  escaping  air  and  gases.  And  in  regard  to  the  height  of  chim- 
neys and  proportions  of  flues,  it  is  always  better  to  be  governed 
by  such  practice  as  has  given  satisfaction  in  that  locality,  and 
with  a  particular  kind  of  fuel,  than  to  be  guided  by  any  theory, 
however  scientific.  The  sectional  area  of  the  flue  is  what  is  termed 
the  calorimeter  of  the  boiler,  and  the  calorimeter,  divided  by  the 
length  of  the  flue  in  feet,  is  termed  the  vent.  The  flues  of  all 
boilers  diminish  in  their  calorimeter  as  they  approach  the  chim- 
ney, as  the  smoke  contracts  in  volume  in  proportion  as  it  passes 
through  the  heat. 

Funnels. — The  area  of  the  funnels  of  steamships,  tug-boats,  and 
ferry-boa^s  varies  considerably  with  different  builders  and  in  dif- 
ferent countries.  The  number  of  circular  inches  p^  nominal  horse- 
power is  given  in  the  following  table,  for  several  makers. 

Highest,  15-14]  Highest,  12-96  Highest,  14*45  Highest,  16-40  Highest,  14-06 
Mean,  M'lO  Mean,  11*79  Mean,  13*94  Mean,  15*94  Mean,  13*12 
Low,      13*01  Low,      10*89  Low,      12*96  Low,      15*14  Low,  12*17 

Mean  Total,  13*78 

These  are  all  for  low  pressures.  For  high  pressure,  the  num- 
ber of  inches  varies  from  9*11  to  6*02,  mean  7*07.  The  funnel 
should  evidently  bear  a  proportion  to  the  amount  of  heated  air 
and  smoke  passing  through  it,  which  must  bear  a  nearer  propor- 
tion to  the  horse- power  than  to  the  surface  of  the  fire-grate. 
Where  the  fire-grate  is  small,  a  large  quantity  must  be  burned  per 
square  foot.  If,  in  one  case,  20  lbs.  of  coal  are  burned  per  square 
foot  per  hour,  and  in  another  40  lbs.,  and  the  funnels  are  proper- 


THE   ENGINEER'S  HANDY-BOOK. 


473 


tioned  to  the  fire-grate,  they  will  not  be  proportioned  to  their  re- 
quirements. 

Rule  for  finding  the  required  area  for  the  chimneys  of  stationary 
boilers. —  Multiply  the  nominal  horse-power  of  the  boiler  by  112, 
and  divide  the  product  by  the  square  root  of  the  height  of  the 
chimney  in  feet.  The  quotient  will  be  the  required  area  in  square 
inches. 

A  well-proportioned  and  moderately  high  smoke-stack  is  to  be 
preferred  for  sea-going  steam-vessels,  as  tall  ones  are  difficult  to 
steady  on  account  of  the  oscillation  of  the  vessel,  arising  from  the 
disturbance  of  the  water  and  the  resistance  of  the  wind. 

Superheaters. —  Superheaters  are  steam-chambers  located  in 
the  uptakes  of  marine-boilers  or  at  the  base  of  the  funnel,  and  so 
arranged  that  the  w^aste  heat  from  the  furnaces  may  pass  around 
and  through  them,  prior  to  escaping  up  the  chimney.  They  are 
used  for  drying  the  steam  in  its  transit  from  the  boilers  to  the 
steam-cylinders  of  the  engines.  The  heat  or  flame  passes  through 
the  tubes  and  around  the  shell,  the  steam  being  inside.  They  are 
fitted  with  a  stop-valve,  and  arrangements  for  mixing  the  super- 
heated and  saturated  steam,  or  using  either  independently ;  they 
also  have  safety-valves  similar  to  those  used  on  steam-boilers. 
There  is  no  definite  size  for  superheaters,  as  they  are  not  intended 
for  a  receptacle  for  any  large  amount  of  steam,  but  simply  as  a 
means  of  drying  it.  The  proportionate  area  of  superheating  to  heat- 
ing surface  in  modern  marine-boilers  is  about  1  to  10  square  feet. 

An  interceptep  op  sepapatop  is  a  chamber  attached  to  marine- 
boilers  for  the  purpose  of  intercepting  the  water  carried  out  by  the 
steam.  The  steam  enters  at  the  top  and  strikes  against  a  partition 
plate,  then  passes  under  it  and  escapes  to  the  cylinder;  the  water 
which  enters  with  the  steam  is  collected  in  the  bottom  of  the  box 
and  drawn  off  through  a  valve. 

Smoke. 

Smoke  once  fopmed  in  a  furnace,  flue,  or  chimney  can  never 
be  burned  by  any  mechanical  device  or  arrangement,  nor  can  there 
40* 


474  THE   ENGINEER'S  HANDY-BOOK. 

be  any  advantage  in  incurring  much  expense  in  the  attempt,  ex- 
cept to  abate  a  nuisance,  as  very  little  economy  in  fuel  would  re- 
sult from  the  adoption  of  any  such  device.  A  very  general  idea 
prevails  that,  when  we  see  large  volumes  of  smoke  issuing  from 
the  mouths  of  the  chimneys  of  stationary  boilers,  smoke-stacks 
of  locomotives,  and  funnels  of  marine-boilers,  whenever  fresh  fuel 
has  been  applied,  a  great  waste  of  fuel  is  taking  place ;  this,  how- 
ever, is  a  mistake,  as  about  of  the  volume  is  steam  resulting 
from  the  moisture  expelled  from  the  coal,  wood,  or  shavings  by 
the  application  of  heat ;  besides,  sulphur  and  other  earthy  matters 
which,  like  the  steam,  are  incombustible,  enter  into  and  increase 
the  volume. 

This  may  be  easily  explained  by  stating  that  \  ton  of  water  is 
converted  into  steam  in  the  furnace  for  every  ton  of  bituminous 
coal  consumed,  which  is  an  actual  benefit,  because,  if  the  carbon 
had  not  been  thoroughly  mixed  with  such  a  great  mass  of  steam, 
it  would  have  fallen  in  the  shape  of  a  black  cloud  of  dust  in  the 
locality  where  the  furnace  was  situated,  and  have  become  a  more 
insufferable  nuisance  than  the  smoke.  Smoke  contains  about  20 
per  cent,  of  combustible  and  80  per  cent,  of  incombustible  matter. 
Such  being  the  case,  the  question  would  naturally  arise.  Would  it 
be  advisable  to  incur  much  expense  in  an  attempt  to  consume  80 
per  cent,  of  incombustible  matter,  for  the  purpose  of  gaining  20 
per  cent.  ? 

Feed- Water  Heaters. 

The  benefits  to  be  derived  from  heating  the  feed-water  for 

boilers  by  exhaust  steam  may  be  explained  as  follows :  A  pound 
of  feed-water  entering  a  steam-boiler  at  a  temperature  of  50°  Fah., 
and  evaporated  into  steam  of  60  lbs.  pressure  per  square  inch,  re- 
quires as  much  heat  as  would  raise  1157  pounds  of  water  1  degree. 
A  pound  of  feed-water  raided  from  50°  Fah.  to  220°  Fah.  requires 
987  thermal  units  of  heat,  which,  if  absorbed  from  exhaust  steam 
passing  through  a  heater,  would  be  a  saving  of  15  per  cent,  in 
fuel.    Feed-water,  at  a  temperature  of  200°  Fah.,  entering  a  boiler, 


THE   engineer's  HANDY-BOOK. 


475 


as  compared  in  point  of  economy  with  feed-water  at  50"^,  would 
effect  a  saving  of  over  13  per  cent,  in  fuel ;  and  with  a  well  con- 
structed heater  there  ought  to  be  no  trouble  in  raising  the  feed- 
water  to  a  temperature  of  nearly  212°  Fah. 

If  we  take  the  normal  temperature  of  the  feed-water  at  60°, 
the  temperature  of  the  heated  water  at  212°,  and  the  boiler-press- 
ure at  20  lbs.,  the  total  heat  imparted  to  the  steam  in  one  case  is 
1192-5°  —  60°     1132-5°,  and  in  the  other  case  1192-5°  —  212°  = 

152 

980-5°,  the  difference  being  152°,  or  a  saving  in  fuel  of  j^^^ 

=  13*4  per  cent.  Supposing  the  feed- water  to  enter  the  boiler  at 
a  temperature  of  32°  Fah.,  each  pound  of  water  will  require  about 
1200  units  of  heat  to  convert  it  into  steam,  so  that  the  boiler  will 
evaporate  between  61  and  7i  pounds  of  water  per  pound  of  coal. 
The  amount  of  heat  required  to  convert  a  pound  of  water  into 
steam  varies  with  the  pressure,  as  will  be  seen  by  the  following 
table : 

TABLE 


SHOWING  THE  UNITS  OF  HEAT  REQUIRED  TO  CONVERT  ONE  POUND  OF 
WATER,  AT  THE  TEMPERATURE  OF  32°,  INTO  STEAM  AT  DIFFERENT 
PRESSURES. 


Pressure  of 
Steam  in  Lbs. 
per  square 
INCH  BY  Gauge. 

Units  of  Heat. 

Pressure  of 
Steam  in  Lbs. 
per  square 
inch  by  Gauge. 

Units  of  Heat. 

1 

1-148 

110 

1-187 

10 

1-155 

120 

1-189 

20 

1-161 

130 

1-190 

30 

1-165 

140 

1-192 

40 

1-169 

150 

1-193 

50 

1-173 

160 

1-195 

60 

1-176 

170 

1-196 

70 

1-178 

180 

1-198 

80 

1-181 

190 

1-199 

90 

1-183 

200 

1-200 

100 

1-185 

476         THE  engineer's  handy-book. 


If  the  feed -water  has  any  temperature,  the  heat  necessary  to 
convert  it  into  steam  can  easily  be  computed.  Suppose  that  its 
temperature  is  65°,  and  that  it  is  to  be  converted  into  steam  hav- 
ing a  pressure  of  80  lbs.  per  square  inch,  the  difference  between 
65  and  32  is  33 ;  subtracting  this  from  1181  (the  number  of  units 
of  heat  required  for  feed- water  having  a  temperature  of  32°),  the 
remainder,  1148,  is  the  number  of  units  for  feed-water  with  the 
given  temperature. 

Technical  Terms  applied  to  Adjuncts  of  the  Steam -Boiler. 

Angle-irons. — Irons  used  for  the  purpose  of  staying  steam- 
boilers.    See  page  400. 

Air-casing. —  An  arrangement  attached  to  fire-  and  smoke-box 
doors  for  the  purpose  of  preventing  radiation  of  heat. 

Blast-pipe.  —  A  small  pipe  used  to  blow  steam  into  the  fun- 
nels of  marine-boilers  for  the  purpose  of  exciting  the  draught  in 
the  furnace. 

Blow-off  cocks. — Cocks  used  for  blowing  the  water  out  of 
steam-boilers. 

Check-valve.  —  A  valve  used  to  retain  the  water  in  steam- 
boilers,  and  relieve  the  feed  apparatus  from  the  pressure. 

Check-chamber. — The  chamber  in  which  the  check-valve 
operates. 

Connecting-pipes. —  The  pipes  which  connect  check-valves  with 
steam-boilers. 

Crown-sheet. — That  part  of  fire-box  boilers  (locomotive  or 
marine)  directly  over  the  fire. 

Crown -bars. — Bars  placed  on  the  upper  side  of  crown-sheets, 
in  the  water-space,  for  the  purpose  of  strengthening  them. 


THE   ENGINEER\s  HANDY-BOOK. 


477 


Crown -braces. —  Braces  attached  to  the  crown-bars,  and  to  the 
shells  and  domes  of  boilers,  for  the  purpose  of  resisting  the  press- 
ure exerted  on  the  flat  surfaces  of  crown-sheets. 

Dashers.  —  Iron  plates  which  are  sometimes  attached  to  the  in- 
side of  steam-boilers  to  prevent  the  cold  water,  as  it  enters,  from 
striking  the  tubes. 

Dead-plate. — The  solid  iron  plate  which  fills  the  space  between 
the  end  of  the  grate-bars  and  the  fire-door  of  boiler-furnaces. 

Deflector. —  An  arrangement  employed,  in  the  furnaces  of  loco- 
motives and  marine-boilers,  for  the  purpose  of  mixing  the  air  and 
gases  arising  from  the  combustion  of  the  fuel,  and  causing  them 
to  ignite. 

Diaphragm-plate. — A  perforated  plate,  used  in  the  steam-domes 
of  locomotives  and  marine-boilers,  to  prevent  the  water  from  being 
carried  over  into  the  cylinder  with  the  steam. 

Dome. — An  elevated  chamber  on  the  top  of  steam-boilers,  from 
which  the  steam  is  generally  taken  for  the  cylinders. 

Dome-stays. — Stays  employed,  in  the  domes  of  locomotives  and 
marine-boilers,  for  the  purpose  of  strengthening  them. 

Gasket. — A  packing  employed  for  making  the  man-  and  hand- 
holes  of  steam-boilers  steam-  and  water-tight. 

Gauge-cocks. —  Cocks  used  on  the  front-head  of  steam-boilers 

by  which  to  ascertain  the  height  of  the  water. 

Grummet. —  A  packing  of  hemp,  used  between  the  flanges  of 
steam-  and  water-pipes,  for  the  purpose  of  making  them  steam- 
and  water-tight. 

Stay-tubes. — Tubes  used  for  bracing  marine-boilers.  They  are 
generally  made  of  thicker  material  than  either  the  ordinary  fire- 
or  water-tubes. 


478 


THE  engineer's  HANDY-BOOK. 


Spanner-guard. —  An  arrangement  employed  to  secure  cocks 
and  valves,  connected  with  marine-engines  and  boilers,  from  being 
opened  or  closed  by  accident. 

Scum-cocks. — Cocks  employed  to  blow  off  extraneous  sub- 
stances from  the  surface  of  the  water  in  steam-boilers. 

Spectacles. —  Pieces  of  iron,  with  concave  sides,  employed  as 
braces  between  the  tubes  of  marine-boilers,  generally  for  the  pur- 
pose of  stopping  leaks. 

Tube-sheets. — The  sheets  into  which  the  tubes  are  inserted  at 

each  end  of  the  boiler. 

Knees. — Brackets  riveted  to  the  sides  of  steam-boilers,  for  the 
purpose  of  sustaining  them  on  their  supports. 

Waist. — A  term  applied  to  the  cylindrical  part  of  locomotive- 
or  marine-boilers. 

Instructions  for  the  Care  and  Management  of  Steam- 

Boilers. 

On  first  entering  a  boiler-room  in  the  morning,  ascertain  whether 
the  water  stands  at  the  proper  level  or  not. 

Never  start  a  fire  under  a  boiler  until  you  are  satisfied  there  is 
suflScient  water  in  it. 

On  taking  charge  of  an  engine  and  boiler,  first  ascertain  if 
there  is  suflScient  water  in  the  boiler,  and  then  trace  out  the  pipes 
and  connections  between  the  engine,  boiler,  and  pumps. 

In  starting  a  fresh  fire  under  a  boiler  while  it  is  cold,  always 
allow  it  to  burn  gradually  at  first,  in  order  to  bring  all  the  parts 
of  the  boiler  to  a  uniform  temperature. 

Never  blow  out  a  boiler  under  a  head  of  steam,  as  the  heat 
remaining  in  the  boiler  will  bake  the  scale  and  mud  on  the  sheets 
and  flues,  after  which  it  will  be  impossible  to  soften  it  again. 


THE   ENGIl5rEER\s  HANDY-BOOK. 


479 


When  preparing  to  clean  boilers,  allow  them  to  cool  down, 
and  the  water  to  remain  in  them  until  ready  to  commence  clean- 
ing. 

Never  fill  a  boiler  with  cold  water  while  the  shell,  flues,  or 
tubes  are  hot,  as  the  contraction  induced  by  the  tube  in  cooling 
will  have  an  injurious  effect. 

Boilers,  under  which  a  forced  draught  is  used,  require  to  be 
cleaned  oftener  than  when  the  draught  is  natural. 

Never  carry  a  higher  pressure  of  steam  than  is  necessary,  nor 
allow  the  water  to  rise  above  the  second  gauge-cock  in  the  boiler 
when  the  engine  is  running. 

Before  starting  a  fire  under  a  boiler,  place  a  small  quantity  of 
coal  on  the  grates,  to  prevent  them  from  being  warped  by  the 
extra  heat  of  the  new  fire. 

Boilers  should  be  cleaned  and  examined  inside  and  out  every 
three  months. 

Never  neglect  to  blow  out  and  clean  boilers,  even  although 
solvents  are  used  for  the  prevention  and  removal  of  scale. 

Never  put  a  new  boiler  into  service  until  examined  thoroughly 
for  the  purpose  of  ascertaining  if  the  boiler-makers  have  neglected 
to  remove  all  lamps,  hammers,  tools,  etc. 

Never  open  a  steam-valve,  on  a  boiler  under  pressure,  quickly, 
for  the  purpose  of  allowing  steam  to  escape  into  the  atmosphere, 
or  into  a  boiler  containing  a  less  pressure,  as  it  is  attended  with  a 
certain  amount  of  danger,  and  may  possibly  produce  an  explo- 
sion. 

Clean  the  flues  or  tubes  of  the  boiler  at  least  once  a  week,  and 
never  allow  ashes  or  cinders  to  accumulate  under  the  grates. 

Never  throw  water  around  the  furnaces  of  fire-box  boilers. 

If  the  water  should,  from  any  unforeseen  cause,  become  danger- 
ously low,  draw  the  fire,  allow  the  boiler  to  cool  down,  and  neither 
admit  feed-water  nor  disturb  the  safety-valve. 

In  case  the  supply  of  water  should  be  temporarily  cut  off,  owing 
to  the  derangement  of  a  pump,  the  bursting  of  a  pipe,  or  any  other 
cause,  stop  the  engine,  cover  the  fire  with  fresh  coal,  and  shut  the 


480 


THE   ENGINEER'S  HANDY-BOOK. 


damper,  so  as  to  retain  a  sufficient  quantity  of  water  in  the  boiler 
to  start  on. 

When  it  becomes  necessary  to  blow  out  a  certain  quantity  of 
the  water  from  a  boiler  every  day,  the  hand  should  never  be  re- 
moved from  the  cock  or  valve,  as  any  diversion  of  a  person's  at- 
tention from  it  may  allow  too  much  to  be  blown  out,  and  the 
boiler  be  ruined. 

In  all  cases  where  it  is  possible,  regulate  the  feed- water  so  as  to 
send  it  into  the  boiler  in  a  steady  stream. 

When  fresh  water  is  used  in  marine-boilers,  it  is  best  to  use  salt 
water  for  a  short  time  w^hen  first  put  into  use,  in  order  to  cover 
the  parts  with  a  thin  coat  of  scale.  This  prevents  them  from 
being  injured  by  the  action  of  fresh  water. 

The  term  salting  marine-boilers,  means  that  the  flues,  tubes, 
and  crown  are  covered  with  a  thick  coating  of  salt,  which  prevents 
the  water  from  coming  in  contact  with  the  iron.  This  induces 
cracking  and  burning  of  the  parts  so  coated,  besides  causing  a 
great  waste  of  fuel. 

The  parts  of  marine-boilers  most  likely  to  suffer  from  an  in- 
sufficiency of  water  are  the  tubes  and  crowns  ;  but  the  water  can- 
not become  low  in  marine-boilers  from  accident,  as  they  can  be 
fed  either  from  the  boiler  feed-pumps,  circulating,  independent, 
donkey,  or  bilge  pumps. 

If  a  tube  becomes  leaky  in  the  tube-sheet,  it  may  be  made 
tight  by  inserting  a  tapering  iron  ferule  about  of  an  inch 
larger  than  the  inside  diameter  of  the  tube. 

If  a  tube  splits,  it  may  be  plugged  with  either  iron  or  wooden 
plugs,  whichever  is  most  convenient.  Iron  is  best  for  the  end 
next  the  furnace,  while  wood  will  answer  for  the  smoke-box  end. 

Boiler  Materials. 

Boiler  making  now  holds  an  important  place  among  the  mechan- 
ical arts.  Its  progress  has  been  aided  chiefly  by  the  enormous 
growth  of  the  steam-engine  as  the  prime  mover,  by  the  increased 


THE    engineer's  HANDY-BOOK. 


481 


facilities  afforded  for  procuring  suitable  materials,  and  by  the  irn- 
provements  made  in  working  them.  In  the  early  days  of  the 
steam-engine,  boilers  of  copper  and  cast-iron  were  used  for  gener- 
ating steam,  but  they  were  seldom  subjected  to  a  pressure  higher 
than  that  of  the  atmosphere ;  but  when  pressures  of  3  to  4  or  even 
7  atmospheres  came  into  use,  cast-iron  was  found  to  be  unreliable 
and  treacherous,  for  which  reason  it  was  discarded  in  favor  of 
wrought  iron,  which  was  not  employed  at  first,  in  consequence  of 
the  difficulty  found  in  working  it  and  in  making  steam-tight  joints. 
It  has,  however,  of  late  years  become  the  material  employed  to 
the  almost  entire  exclusion  of  all  others.  It  has  been  more  ex- 
tensively employed  in  the  construction  of  steam-boilers,  for  the 
past  thirty  years,  than  any  other  material,  on  account  of  its  great 
tensile  strength,  its  ductility,  power  of  bearing  sudden  and  trying 
strains,  trustworthy  nature,  the  ease  with  which  it  can  be  welded, 
riveted,  patched,  or  mended,  and  its  moderate  first  cost,  etc. 

The  first  quality  to  be  sought  for  in  boiler  materials  is  strength. 
This  does  not  necessarily  imply  the  mere  power  to  resist  being 
torn  asunder  by  a  dead  weight,  as  in  a  testing-machine ;  but  the 
quality  to  withstand,  without  injury,  the  varying  shocks  and 
strains  to  which  boilers  are  exposed.  An  inferior  quality  of  plates 
cannot  be  relied  upon  to  bear  the  ordeal  of  heating  and  cooling 
repeatedly,  as  they  invariably  warp  and  twist,  showing  defects  of 
manufacture ;  more  especially  in  the  process  of  cold  bending,  when 
minute  fractures  often  occur  on  the  outer  surface  of  the  plates  of 
stubborn  or  inferior  qualities  of  iron. 

The  defect  most  commonly  revealed  in  working  boiler-plates  is 
want  of  lamination.  This  defect  arises  from  the  imperfect  welding 
of  the  several  layers  which  make  up  the  thickness  of  the  plate,  and 
is  usually  caused  by  interposing  sand  or  cinder,  which  has  not 
been  expelled  by  hammering  or  rolled  out  during  the  process  of 
;  manufacture.    This  is  more  frequent  in  thick  than  in  thin  plates, 
and  is  sometimes  very  difficult  to  detect  in  cold  plate,  although 
I  often  discernible  in  the  hot.    It  also  often  happens  that  plates 
i  which  are  passed  as  quite  sound,  on  careful  external  examination 
!  41  2F 


482 


THE   engineer's  HANDY-BOOK. 


are  found  to  be  severely  laminated  when  subjected  to  heating  and 
hammering,  and  prove  totally  unfit  for  use. 

Blisters  are  of  a  similar  nature,  and  arise  from  the  same  cause 
as  lamination.  Sometimes  they  appear  as  mere  surface  defects, 
and  are  of  no  consequence ;  but  their  appearance  may  be  an  in- 
dication of  want  of  care  or  skill  in  the  making  of  the  plate,  and 
should  always  excite  suspicion.  It  frequently  happens  that  these 
defects  pass  undetected  after  the  closest  scrutiny  and  test  by  ham- 
mering, but  disclose  themselves  soon  after  the  boiler  is  set  to  work, 
especially  if  the  plates  be  exposed  to  sudden  variations  of  tem- 
perature. In  the  plates  over  the  fire-grate  of  an  externally  fired 
boiler,  such  a  blister  may  prove  a  very  serious  defect,  and  often 
necessitates  the  cutting  out  and  replacement  of  the  sheet.  Infe- 
rior brands  of  iron  will  rapidly  show  unmistakable  signs  of  weak- 
ness when  placed  under  the  trying  ordeal  of  bearing  the  alternate 
impingement  of  a  fierce  flame  and  currents  of  cold  air.  The 
rapid  variations  of  temperature  caused  by  the  sudden  and  frequent 
openings  of  the  furnace  door,  and  passage  of  cold  air  through  the 
grate-bars,  will  soon  tell  on  even  the  best  iron,  but  more  quickly 
on  that  of  an  inferior  brand. 

Characteristics  of  boiler-iron  when  broken.  On  breaking  ? 
plate  or  bar  of  wrought-iron,  the  fracture  presents  an  appearance 
by  which  the  quality  of  the  iron  may,  in  some  measure,  be  deter- 
mined. The  fracture  is  designated,  on  the  one  hand,  as  fibrous, 
tough,  silky,  close-grained,  etc.,  or,  on  the  other  hand,  crystalline, 
coarse,  open-grained,  brittle,  and  cold-shut.  When  broken  sud- 
denly, the  best  qualities  of  plate  and  bar  iron  exhibit  a  fine, 
close-grained,  uniform  crystalline  fracture,  even  silky,  of  a  light 
silver  color ;  the  appearance  in  the  harder  descriptions  approach- 
ing to  thai  of  steel.  The  appearance  of  indiflferently  refined  and 
inferior  qualities  is  coarser,  usually  of  a  darker  color,  more  or  less 
uneven,  or  open,  exhibiting  large  facets,  and  approaching  some 
descriptions  of  cast-iron.  When  broken  gradually,  good  iron 
presents  a  well  drawn  out,  close  fibre,  of  light  greenish  hue,  whilst 
inferior  qualities  give  a  shorter,  more  open,  and  darker  fibre. 


THE   engineer's    II  A  N  D  Y -BOOK  . 


483 


When  good  ductile  iron  is  gradually  torn  asunder,  it  stretches 
to  a  considerable  extent,  causing  a  diminution  of  sectional  area  at 
the  fractured  part,  which  should  always  be  compared  with  the 
original  sectional  area  of  the  specimen  in  judging  of  the  quality. 
An  inferior  bar  or  plate  may  bear  as  great  a  tensile  strain  as  a 
similar  specimen  of  superior  quality  ;  but  on  comparing  their  frac- 
tured areas,  it  will  generally  appear  that  the  latter  has  been  drawn 
out  considerably,  whilst  the  inferior  specimen,  having  stretched 
but  little,  has  not  sensibly  diminished  at  the  fracture.  This  is 
owing  to  the  fact  that  good  ductile  iron,  when  sudden  strains  occur, 
will  stretch,  while  badly  refined  will  snap.  Wrought-iron  changes 
from  fibrous  to  crystalline,  after  enduring  long-continued  cold 
hammering,  vibration,  tension,  jarring,  and  other  strains,  after  long 
exposure  to  the  influence  of  heat,  or  alternate  expansion  and  con- 
traction whenever  it  has  been  used  for  the  plates  of  a  boiler  fur- 
nace. Even  the  very  best  plates,  after  from  ten  to  twenty  years* 
use  in  a  boiler,  have  frequently  been  found  to  break  without 
stretching,  at  the  same  time  displaying  a  crystalline  fracture. 

It  has  been  said  that  this  shows  that  a  change  has  taken  place 
in  the  nature  of  the  material,  and  that,  from  being  fibrous  and 
tough,  it  has,  by  some  unexplained  cause,  become  crystallized  and 
brittle,  or  that  it  has  lostjts  nature  in  consequence  of  the  treat- 
ment it  has  undergone,  whatever  that  may  have  been.  There  is 
no  doubt  that  the  strains  and  other  causes  above  mentioned  have 
a  tendency  to  make  good  iron  become  brittle  and  liable  to  snap 
suddenly  under  the  same  treatment  that  would  originally  have 
torn  it  gradually,  and  to  this  extent  a  change  is  produced  in  its 
nature.  This  snapping,  and  not  the  fatigue  of  the  metal,  is  the 
direct  cause  of  the  crystalline  fracture,  w^hich  is  but  a  necessary 
consequence  of  the  suddenness  of  the  breaking,  and  not  a  prop- 
erty of  the  iron  itself.  To  say  it  snaps  readily  because  it  ha^  be- 
come crystalline  is  to  confound  the  cause  with  the  eflTect.  It  is 
erroneous  to  say  the  fibrous  nature  has  passed  out  of  the  iron,  as 
its  ductility  can  to  some  extent,  at  least,  be  restored,  in  most 
cases,  by  simply  heating  to  a  bright  red,  and  slowly  cooling,  the 


484  THE  engineer\s  handy-book. 

iron,  or,  failing  that,  by  hammering  or  rolling  it  while  hot.  By- 
heating  to  redness,  and  suddenly  cooling,  a  piece  of  wrought-iron, 
it  will  become  liable  to  snap,  producing  the  same  effect  as  cold 
hammering.  The  explanation  of  this  is  not  clear,  and  it  may  be 
owing  to  the  loosening  of  the  crystals  into  which  the  composition 
of  the  material  ultimately  resolves  itself.  To  this  cause  may  also 
be  attributed  the  same  tendency  to  snap  after  long-continued  jar- 
ring or  alternate  expansion  and  contraction. 

It  may  be  asserted,  without  fear  of  contradiction,  that  all  boiler- 
plate worthy  of  the  name  is  fibrous ;  whether  its  hardness  makes 
it  liable  to  snap,  and,  therefore,  appear  crystalline,  depends  on  its 
original  character  and  the  treatment  it  has  undergone.  No  fine 
iron  can,  however,  by  any  treatment,  except  burning,  be  made  to 
appear  coarse,  and  the  fibres  of  the  poorest  descriptions  of  iron 
cannot,  without  refining,  be  made  to  appear  fine  and  close-grained. 
From  a  want  of  knowledge  of  the  above  facts,  false  opinions  are 
often  expressed  respecting  the  qualities  of  boiler-plates. 

It  is  no  unusual  thing  to  find  intelligent  mechanics  and  boiler- 
makers  expressing  their  opinions,  at  coroners'  inquests,  on  the 
quality  of  the  iron  in  exploded  boilers,  without  anything  to  base 
their  opinions  on  except  the  load  per  square  inch  required  to  tear 
the  plates  asunder.  They  seem  to  forget,  if  the  boiler  be  an  old 
one,  that  the  age,  the  position  in  the  boiler  in  which  the  rent  has 
taken  place,  the  amount  of  strain  to  which  it  has  been  exposed, 
and  all  the  circumstances  connected  with  the  occurrence,  should 
be  known  in  order  to  decide  understandingly  as  to  the  quality  of 
the  iron.  It  has  been  shown,  in  numerous  instances,  that  good  duc- 
tile iron  can  be  made  to  appear  crystalline  when  pulled  asunder 
in  the  testing-machine,  by  confining  the  minimum  sectional  area 
where  fracture  will  occur  to  one  point  or  to  a  very  short  length. 

The  general  conclusions  with  regard  to  boiler  material,  which 
may  be  regarded  as  established  from  experiments,  observations, 
and  practice,  thus  far  seem  to  be,  1st,  That  the  laws  of  resistance 
of  the  parts  of  boilers  to  the  internal  pressure  are  sufficiently 
well  established ;  2d,  It  is  of  the  utmost  importance  that  the  ma- 


THE   ENGINEER'S  HANDY-BOOK. 


485 


terials  employed  should  be  of  the  best  quality  as  regards  strength 
and  durability;  and  as  there  are  but  few  manufacturers  of  boiler- 
plates, the  inspection  of  materials,  especially  boiler-plates,  should 
be  made  by  competent  persons,  appointed  for  that  purpose,  at  the 
place  of  manufacture,  which  inspection  should  extend  to  the 
qualities  of  ores  and  the  process  of  manufacture,  the  required 
brands,  stamps,  or  certificates  being  put  on  or  authorized  by  the 
inspectors  in  person.  There  is  much  greater  certainty  of  securing 
the  best  materials  by  an  inspection  of  the  process  of  working,  and 
of  the  raw  materials  employed,  than  by  an  inspection  of  plates 
after  they  have  been  sent  to  market,  when,  judging  from  all  exter- 
nal appearances,  good  and  bad  plates  are  not  easily  distinguished. 

Practical  limits  to  the  thickness  of  boiler-plates. — The  proper 
strength  of  boilers,  in  order  to  enable  them  to  withstand  with 
safety  the  required  pressure  of  the  steam,  is  a  matter  of  much 
importance  as  regards  both  life  and  property,  and  the  responsi- 
bility of  the  proprietors  and  constructors  of  boilers  is  of  so  grave 
a  character  as  to  justify  the  devotion  of  a  much  larger  space  to 
this  subject  than  is  convenient  in  this  work.  The  principles  on 
which  the  strength  of  the  material  depends  may  be  expressed  in 
a  very  few  words,  —  the  strength  being  directly  as  the  thickness 
of  the  metal,  and,  inversely,  as  the  diameter  of  the  boiler. 

So  long  as  the  quality  of  boiler-iron  remains  as  it  is  at  present, 
the  thickness  of  the  plate  may  be  practically  determined  within 
exceedingly  narrow  limits,  as  a  good  boiler  must  be  constructed 
of  plafe  ranging  in  thickness  from  |  to  |  an  inch,  as  anything 
less  than  the  former  cannot  be  properly  caulked,  and  any  thick- 
ness greater  than  the  latter  is  difficult  to  rivet  without  the  aid  of 
machinery.  A  thickness  of  -f  seems  to  have  become  the  standard 
thickness  for  all  diameters  of  boilers  intended  to  sustain  a  high 
pressure.  This,  perhaps,  arises  from  the  fact  that  boiler-makers 
seem  to  be  better  acquainted  with  the  practical  limit  to  the  strength 
of  that  thickness,  because  it  has  of  late  years  been  used  more  than 
any  other;  nevertheless,  for  steel,  or  some  of  the  higher  grades  of 
American  plate,  a  less  thickness  will  suffice  for  the  same  pressure. 
41* 


486 


THE   ENGINEER'S  HANDY-BOOK. 


Definitions  of  the  Technical  Terms  Applied  to  the 
Different  Kinds  of  Boiler-Plate. 

C.  No.  I  charcoal  iron  means  that  charcoal  was  the  fuel  em- 
ployed in  the  blast-furnace  when  the  iron  was  smelted.  Such  iron 
is  not  suitable  for  any  purpose  when  exposed  to  a  high  tempera- 
ture. Although  it  is  frequently  used  for  the  shells  of  boilers,  it  is 
very  seldom  employed  for  furnace-sheets. 

C.  H.  No.  I  charcoal  iron,  commonly  called  flange-iron,  is 
manufactured  by  the  same  process  as  C.  No.  1,  with  this  differ- 
ence, that  it  is  reheated  and  hammered,  which  increases  its  com- 
pactness, solidity,  and  strength  as  well  as  its  capacity  for  resisting 
high  temperatures.  C.  H.  No.  1  is  generally  called  cold  blast- 
iron  ;  the  process  of  manufacture  is  as  follows.  The  pig-metal  is 
remelted  and  refined,  or  converted  into  wrought-iron  in  charcoal 
fires,  the  balls  being  hammered  into  blooms.  These  blooms  are 
reheated  in  reverberatory  furnaces,  and  then  rolled  into  slabs. 
These  pieces  are  called  covers,  between  two  of  which  clippings 
of  boiler-plate  and  other  wrought-iron  scraps  are  placed,  after 
which  the  mass  is  brought  to  welding  heat  and  passed  between 
heavy  rollers.  The  greatest  danger  to  be  encountered  in  this 
process  arises  from  the  imperfect  welding  of  the  pieces.  It  is 
often  due  to  the  slag  which  remains  between  the  coils  when  the 
mass  is  heated.  Iron  manufactured  by  this  process  frequently 
blisters  when  exposed  to  an  intense  heat.  Boiler-plate  should 
never  be  manufactured  by  this  process,  as  it  is  generally  of  infe- 
rior quality,  and  always  proves  deceptive.  The  only  advantage 
in  making  it  in  this  manner  is  cheapness.  C.  H.  No.  1  charcoal 
iron  is  produced  by  piling  one  slab  upon  another  at  right  angles 
with  each -other,  and  exposing  them  to  a  high  welding  heat,  after 
which  they  are  rolled  and  hammered,  great  care  being  taken  both 
in  the  selection  of  the  material  and  in  the  rolling  and  hammering. 

Fire-box  iron  is  a  kind  of  plate  manufactured  exclusively  for 
furnaces.  It  is  produced  in  the  same  manner  as  C.  H.  No.  1,  with 
this  difference,  that  it  is  subjected  to  two  or  three  more  processes 


THE   engineer's  HANDY-BOOK. 


487 


of  heating,  rolling,  and  hammering.    There  are  many  grades  of 
I   this  kind  of  iron,  resulting  from  the  details  of  the  processes  which 
I   are  customary  in  the  different  plate  mills,  and  the  care  with  which 
I   the  iron  is  selected.    The  names  of  the  different  manufacturers 
furnish  a  better  guarantee  than  the  stock  of  knowledge  possessed 
by  the  most  talented  experts. 

Iron  produced  from  covers  filled  with  iron  scrap  will  blister, 
unless  the  slag  is  expelled  by  patient  and  careful  heating,  rolling, 
and  hammering.  Such  iron,  if  used  for  fire-box  plates,  should  be 
tested  as  follows.  Lay  the  plate  off  with  a  straight-edge,  and 
pencil  or  chalk  in  squares  of  about  one  foot  each ;  then,  with  a 
light  steel  hammer,  strike  the  surface  of  each  square  about  one 
inch  apart,  when,  if  there  are  any  defects  in  the  iron,  they  will  in 
all  probability  be  made  manifest  by  the  sound.  As  soon  as  each 
square  is  finished,  it  should  be  cancelled,  in  order  to  prevent  repe- 
tition.  If  the  iron  is  perfect,  it  will  give  out  a  clear  sound. 

From  the  foregoing,  it  will  be  seen  how  much  depends  on  the 
character  of  the  material,  and  the  care  taken  in  the  process  of  man- 
ufacture. It  is  well  known  that  in  many  instances  the  iron  in  dif- 
ferent plate  mills  is  the  same  in  every  respect,  and,  while  the  pro- 
cesses through  which  it  has  passed  are  the  same  to  all  appearance, 
on  examination  it  has  been  found  that  that  produced  by  one  mill 
was  of  an  excellent  quality,  while  that  produced  by  another  was 
of  a  very  inferior  grade.  As  a  general  rule,  boiler-plate  that  can 
be  bent  at  right  angles,  when  heated  to  a  red  heat,  without  showing 
any  cracks,  may  be  relied  upon.  But  the  indications  of  superior- 
ity wiirbe  strengthened,  if  the  iron  can  stand  the  test  of  bending 
at  right  angles  when  cold,  as  none  but  the  finest  grades  can  bear  it. 

Steel  boiler-plates  are  generally  made  of  puddled  steel,  in  which 
the  ordinary  puddling  process,  by  means  of  which  wrought-iron  is 
made  from  pig-iron,  is  arrested  at  the  point  required  for  the  carbon- 
ization of  the  steel.  Homogeneous  steel  plates  are  produced  from 
cast-steel,  which  is  formed  by  melting  the  finest  grades  of  wrought- 
iron  in  crucibles  with  carbonaceous  matter,  after  which  the  ingots 
are  reheated  and  rolled  into  plates  of  the  desired  thickness. 


488 


THE   ENGINEER'S  HANDY-BOOK. 


The  Buckeye  Automatic  Cut-OflF  Engine. 

The  cuts  on  pages  489,  490,  represent  a  front  and  back  view  of 
the  Buckeye  automatic  cut-off  steam-engine.  As  may  be  observed, 
the  bed-plate  is  a  modification  of  the  Corliss  or  girder-frame  pattern, 
a  design  which  possesses  sufficient  rigidity,  without  extra  weight 
of  metal.  It  is  faced  up  at  one  end  to  receive  the  cylinder,  and 
at  the  other  the  main  pillow-block.  The  cylinder  contains  the 
steam-ports,  but  not  the  exhaust-ports ;  and,  as  the  valve-faces  are 
as  near  the  cylinder  as  is  consistent  with  suflScient  strength,  the 
clearance  is  reduced  to  a  minimum,  a  feature  which  renders  the 
engine  very  economical  in  the  use  of  steam.  The  cross-head  is 
made  in  halves,  is  held  together  by  bolts,  and  is  attached  to  the 
piston-rod  by  means  of  a  thread  on  the  rod.  The  cross-head  shoes 
move  in  flat  guides,  and  can  be  easily  adjusted  by  me£  lis  of  screws 
and  jam-nuts. 

The  main  steam -valve  is  driven  by  a  fixed  eccentric  in  the  usual 
manner.  An  adjustable  eccentric,  the  position  of  which  on  the 
shaft  is  under  the  control  of  the  governor,  works  the  cut-off  valves. 
A  novel  feature  of  the  cut-off  valve-gear  is  a  rock-shaft  working 
in  a  bearing  in  the  rocker-arm  belonging  to  the  main  valve-gears. 
The  adjustable  eccentric  is  attached  to  a  pendant  arm  on  the  outer 
end  of  it,  and  a  similar  but  vertical  arm  on  the  inner  end  con- 
nects it  to  the  head,  and  thus  works  the  cut-off*  valve.  The  effect 
of  this  device  is  to  secure  a  correct  movement  of  the  cut-off  valves 
relatively  to  their  seats  in  the  moving  main  valve,  and  at  the  same 
time  to  effect  a  degree  of  adjustment  of  the  cut-off  exactly  cor- 
responding to  the  degree  of  change  in  the  angular  position  of  the 
eccentric,  neither  of  which  is  possible  without  such  an  arrange- 
ment. These  engines  are  in  very  general  use,  and  are  said  to  be 
very  durable  and  economical.  One  of  them  on  exhibition  at  the 
Centennial  Exposition  at  Philadelphia  attracted  considerable  at- 
tention. They  are  manufactured  (both  condensing  and  non-con- 
densing) by  the  Buckeye  Engine  Company,  Salem,  Ohio,  under 
J.  W.  Thompson's  patent. 


THE   engineer's  HANDY-BOOK. 


48y 


490 


THE   engineer's  HANDY-BOOK. 


THE   engineer's  HANDY-BOOK. 


491 


Questions, 

THE  ANSWERS  TO  WHICH  MAY  BE  FOUND  IN  THE  TEXT. 

Define  the  term  steam-boiler. 

Why  is  there  more  need  of  accurate  information  in  relation  to 
the  steam-boiler  than  to  the  steam-engine  ? 

What  causes  affect  the  strength  and  durability  of  steam-boilers? 

What  qualities  are  most  desirable  in  a  steam-boiler? 

Describe  the  nature  and  effect  of  the  destructive  forces,  both 
chemical  and  mechanical,  that  act  on  steam-boilers. 

Of  what  form  should  a  boiler  be  constructed  to  embody  the 
greatest  strength  ? 

Give  the  names  of  the  different  boilers  in  use,  both  land  and 
marine,  their  advantages  and  disadvantages. 

State  the  proportion  of  heating-surface  to  grate-surface  suflScient 
to  constitute  a  horse-power  in  a  steam-boiler. 

What  conditions  will  influence  the  amount  of  water  which  one 
pound  of  coal  will  evaporate  in  a  steam-boiler,  also  the  maximum 
and  minimum  evaporation  per  pound  of  coal  ? 

Give  the  principal  causes  which  induce  foaming  in  steam-boilers. 

Give  the  names  of  the  different  adjuncts  of  steam-boilers. 

Give  the  rule  for  finding  the  bursting-pressure  of  steam-boilers. 

Give  the  rule  for  finding  the  safe  working-pressure  of  steam- 
boilers. 

Give  the  rule  for  finding  the  internal  strain  caused  by  the  press- 
ure of  steam  on  the  shells  of  steam-boil^s. 


492         THE  engineer's  handy-book. 

Give  the  rule  for  finding  the  pressure  per  square  inch  of  sectional 
area  on  the  crown-sheets  of  steam-boilers. 

Give  the  rule  for  finding  the  safe  external  pressure  of  boiler- 
flues. 

Give  the  rule  for  finding  the  collapsing-pressure  for  boiler-flues. 

Give  the  rule  for  finding  the  number  of  square  feet  of  heating- 
surface  in  any  given  number  of  flues  or  tubes. 

Give  the  rule  for  finding  the  relative  strength  of  single-  and 
double-riveted  seams  of  steam-boilers. 

Give  the  rule  for  finding  the  strength  of  stays  for  steam-boilers. 

Give  the  rule  for  finding  the  heating-surface  for  any  steam- 
boiler. 

Explain  the  object  of  stay-bolts,  their  breaking-strength,  etc. 

Explain  the  causes  which  induce  the  formation  of  scale  in  steam- 
boilers. 

Give  the  chemical  ingredients  of  the  scale  w^hich  forms  in  steam- 
boilers. 

Explain  the  causes  of  the  loss  of  fuel  induced  by  incrustation 
in  steam-boilers. 

What  are  the  causes  which  induce  deterioration  in  sfeam-boilers? 

Does  the  tensile  strength  of  boiler-iron  increase  by  the  appli- 
cation of  heat?  and,  if  so,  up  to  what  degree  Fah.  does  it  increase? 

What  are  the  causes  of  corrosion  in  steam-boilers?  and  what 
analogy  does  corrosion  bear  to  combustion  ? 

What  advantage  has  mechanical  firing  over  manual  firing,  and 

vice  versa  ? 


THE   engineer's    HANDY-BOOK.  493 

Give  the  technical  terms  as  applied  to  firing. 

Give  the  technical  terms  employed  in  relation  to  steam-boilers. 

Explain  the  cause  of  friction  in  riveted  seams. 

What  is  the  object  of  caulking? 

Explain  the  causes  of  steam-boiler  explosions. 

What  is  the  object  of  a  safety-valve  on  a  steam-boiler  ? 

Give  the  rule  for  finding  the  weight  necessary  to  be  placed  on 
a  safety-valve  lever  when  the  area  of  the  valve,  pressure,  etc.,  are 
given. 

Give  the  rule  for  finding  the  pressure  per  square  inch  against 
the  safety-valve  when  the  area  of  the  valve,  weight  of  ball,  etc., 
are  known. 

Give  the  rule  for  finding  the  pressure  at  which  the  safety-valve 
is  weighted  when  the  length  of  the  lever,  the  weight  of  the  ball, 
etc.,  are  known. 

Give  the  rule  for  finding  the  centre  of  gravity  of  taper  levers 
j)f  safety-valves. 

Explain  the  comparative  advantages  and  disadvantages  of  dead- 
weight, spring,  and  lock  safety-valves. 

Explain  the  cause  of  draught  in  chimneys. 

Explain  the  advantages  and  disadvantages  of  square,  oval,  and 
circular  chimneys. 

Give  the  rule  for  finding  the  area  of  a  chimney  or  funnel  neces- 
sary to  produce  a  suflScient  draught  to  consume  a  given  quantity 
of  fuel  in  a  given  time. 

What  are  the  advantages  of  superheaters? 
42 


494         THE  engineer's  handy-book. 
What  is  the  object  of  an  interceptor? 
What  ape  the  chemical  ingredients  which  constitute  smoke? 

Can  smoke,  when  once  formed,  be  consumed  by  any  mechanical 

process  ? 

Does  the  formation  of  smoke  incur  a  waste  of  fuel,  and,  if  so, 
to  what  extent? 

Explain  the  meaning  of  the  technical  terms  applied  to  the  dif- 
ferent adjuncts  of  steam-boilers. 

What  course  should  an  engineer  or  fireman  pursue  when  first 
entering  the  boiler-room  in  the  morning? 

What  precaution  should  be  taken  before  starting  a  fire  under 
a  boiler  ? 

What  course  should  an  engineer  adopt  on  taking  charge  of  an 
engine  and  boiler  for  the  first  time? 

How  should  the  fire  be  regulated  when  first  started  under  a 
boiler  ? 

Under  what  conditions  should  a  boiler  be  blown  out? 

What  should  be  the  condition  of  a  boiler  when  it  is  to  be  filled 
with  cold  water  ? 

What  course  should  be  adopted  with  boilers  before  cleaning? 

How  should  boilers  be  treated  when  21,  forced  draught  is  used? 

How  should  the  pressure  in  a  boiler  be  regulated  ? 

How  should  the  kindling  material  be  placed  on  the  grate  pre- 
paratory to  starting  a  fire  ? 

How  often  should  steam-boilers  be  cleaned  ? 


THE   ENGINEER\s    HANDY-BOOK.  495 

Should  the  cleaning  of  boilers  be  neglected,  when  solvents  are 
used  for  the  prevention  and  removal  of  scale? 

What  precautions  should  be  taken  before  new  boilers  are  put 
into  service? 

How  often  should  the  flues  or  tubes  of  boilers  be  cleaned  ? 

What  course  should  be  adopted  in  case  the  water  in  a  boiler 
becomes  dangerously  low  ? 

What  course  should  be  pursued  in  case  the  water-supply  should 
become  interrupted  for  any  length  of  time  ? 

What  precaution  should  an  engineer  take,  in  case  it  becomes 
necessary  to  blow  out  a  certain  quantity  of  water  every  day  ? 

How  should  the  supply  of  feed-water  be  regulated? 

What  advantages  are  gained  by  filling  marine-boilers  with  salt- 
water for  the  first  time  ? 

What  is  the  meaning  of  the  term  "salting"  when  applied  to 
marine-boilers? 

What  parts  of  any  class  of  steam-boilers  are  most  likely  to  suf- 
fer from  the  effects  of  heat  ? 

What  is  the  most  practical  method  to  adopt  in  case  a  boiler- 
tube  should  become  leaky  ? 

« 

What  course  should  an  engineer  or  fireman  adopt  in  case  a 
tube  should  become  split  ? 

Give  the  characteristics  of  good  boiler  material,  whether  iron, 
steel,  or  copper. 

Give  the  definitions  of  the  technical  terms  applied  to  the  dif- 
ferent kinds  of  boiler-plates. 


496 


THE   engineer's  HANDY-BOOK. 


PART  SEVENTH. 


Air. 

The  atmosphere  is  known  to  extend  at  least  45  miles  above  the 
earth.  Its  aggregate  weight  has  been  calculated  at  upwards  of 
77,000,000,000  of  tons,  or  equivalent  to  the  weight  of  a  solid  globe 
of  lead  60  miles  in  diameter.  Hence,  this  enormous  weight  re- 
poses incessantly  upon  the  earth's  surface,  and  upon  every  object, 
animate  or  inanimate,  solid,  liquid,  or  aeriform.  100  cubic  inches 
of  air  at  the  surface  of  the  earth,  when  the  barometer  stands  at 
34  inches,  and  at  a  temperature  of  60°  Fah.,  weigh  about  31  grains, 
being  thus  about  815  times  lighter  than  water,  and  11,065  times 
lighter  than  mercury.  The  component  parts  of  the  air  are  about 
79  measures  of  nitrogen  gas  and  21  of  oxygen ;  or,  in  other  words, 
air  consists  of  (by  volume)  oxygen,  21  parts ;  nitrogen,  79  parts 
(by  weight) ;  oxygen,  77  parts ;  nitrogen,  23  parts. 

Now,  since  the  air  is  possessed  of  weight,  it  must  be  evident 
that  a  cubic  foot  of  air  at  the  surface  of  the  earth  has  to  support 
the  weight  of  all  the  air  directly  above  it ;  and  that,  therefore,  the 
higher  we  ascend  in  the  atmosphere,  the  lighter  will  be  the  cubic 
foot  of  air ;  or,  in  other  words,  the  farther  from  the  surface  of  the 
earth  the  less  will  be  the  density  of  the  air.  At  the  height  of 
three  and  a  half  miles,  it  is  known  that  the  atmospheric  air  is  only 
half  as  dense  as  it  is  at  the  surface  of  the  earth.  From  the  nature 
t)f  fluids,  it  follows  that  the  atmosphere  presses  against  any  body 
with  which  it  comes  in  contact  —  because  fluids  exert  a  pressure  in 
all  directions  —  upwards,  downwards,  sidewise,  and  obliquely.  Its 
particles  are  so  inconceivably  minute,  that  they  enter  all  substances, 
even  liquids.  It  penetrates  all  the  ramifications  and  innermost 
recesses  of  porous  bodies,  and  is  mixed  up  with  and  circulates  in 
the  blood  of  men  and  animals ;  and  by  the  pressure  of  its  super- 
incumbent strata,  it  is  urged  through  almost  every  substance.  It 


THE   ENGINEf:u'8    II  A  N  T)  Y  -  R O O K  . 


497 


is  this  circulation  through  the  interior  of  the  bodies  of  men  and 
animals  which  counterbalances  its  outer  pressure ;  because,  if  its 
weight  were  not  neutralized,  neither  man  nor  beast  could  walk, 
and  would  be  as  mute  as  statues  of  lead,  and  lips  once  closed  could 
never  again  be  opened. 

The  amount  of  pressure  of  a  column  of  air,  whose  base  is  one 
square  foot  and  whose  altitude  is  the  height  of  the  atmosphere, 
has  been  found  to  be  2156  pounds  avoirdupois,  or  very  nearly  15 
pounds  of  pressure  on  every  square  inch.  Consequently,  it  is  com- 
mon to  state  the  pressure  of  the  atmosphere  as  equal  to  15  pounds 
on  the  square  inch.  If  any  other  gaseous  body  or  vapor  —  such  as 
steam  —  exerts  a  pressure  equivalent  to  15  pounds  on  the  square 
inch,  then  the  force  of  that  vapor  is  said  to  be  equal  to  one  atmos- 
phere. If  the  vapor  be  equal  to  30  pounds  on  every  square  inch, 
then  it  is  equal  to  two  atmospheres,  and  so  on ;  consequently,  the 
atmospheric  pressure  is  capable  of  supporting  about  30  inches  of 
mercury,  or  a  column  of  water  34  feet  high. 

It  is  known  that  the  pressure  of  the  atmosphere  is  not  constant, 
even  at  the  same  place.  At  the  equator,  the  pressure  is  nearly 
constant,  but  is  subject  to  great  changes  in  high  latitudes.  In 
some  countries  the  pressure  of  the  atmosphere  varies  so  much  as 
to  support  a  column  of  mercury  so  low  as  28  inches,  and  at  other 
times  so  high  as  31,  the  mean  being  29*5  ;  thus  making  the  average 
pressure  between  14  and  15  pounds  on  the  square  inch.  But  in 
scientific  books,  generally,  the  pressure  is  understood,  in  round 
numbers,  to  be  15  pounds;  so  that  a  pressure  exerted  equal  to  1, 
2,  3,  4,  etc.,  atmospheres  means  such  a  pressure  as  would  support 
30,  60,  90,  120,  etc.,  inches  in  a  perpendicular  column,  or  15,  30, 
45,  60,  etc.,  pounds  on  every  square  inch. 

The  pressure  of  the  air  differs  at  diflerent  altitudes ;  *  at  7  miles 
above  the  surface  of  the  earth,  the  air  is  four  times  lighter  than 
it  is  at  the  surface;  at  14  miles  it  is  16  times  lighter;  and  at  21 
miles  it  is  64  times  lighter.    It  requires  13,817  cubic  feet  of  air 


*  See  table  on  page  498. 
42*  2G 


498 


THE   ENGINEER'S  HANDY-BOOK. 


to  make  one  pound ;  consequently,  one  cubic  foot  of  air  at  the 
surface  of  the  earth  weighs  527  grains,  or  J  of  an  ounce  avoir- 
dupois; but  under  a  pressure  of  5i  tons  to  the  square  inch,  air 
becomes  as  dense,  and  would  weigh  as  much  per  cubic  foot,  as 
water. 

TABLE 


OF  ALTITUDES  ABOVE  SEA-LEVEL,  AND  THE  CORRESPONDING  ATMOS- 
PHERIC PRESSURES,  DEDUCED  FROM  THE  OBSERVATIONS  OF  THE  HAY- 
DEN  EXPEDITION  TO  THE  ROCKY  MOUNTAINS. 


Location. 

Altitude 
IN  Feet. 

Pressure 

OF  THE 

Atmosphere. 

Altoona,  Pa.  ..... 

1,168* 

14-08 

Cairo,  111  

291-23 

1456 

Cheyenne,  Wy.  Ter  

6,075-28 

11 -48 

Cincmnati,  U.  . 

440* 

14*46 

Cresson,  Pa.  ..... 

2,000- 

1364 

Denver,  Col  

5,196-58 

11-94 

Golden  City,  Col  

5,728-98 

11-67 

Lake  Champlain  .... 

100-84 

14-64 

"    Erie       .       .       .  . 

573-08 

14-39 

"    Huron  ..... 

589-99 

14-38 

"  Michigan  

589-15 

14-39 

"    Ontario.  ..... 

249-99 

14-56 

Louisville,  Ky.        .       .   •  , 

404- 

14-48 

Mt.  Lincoln,  Col  

14,296-66 

7-06 

New  Albany,  Ind.    .       »       .  . 

379-75 

14-5 

Ogden,  Utah    .       .       .       »  . 

4,303-3 

12-42 

Omaha,  Neb  

977-9 

14-18 

Pike's  Peak,  Col.     .       o       .  . 

14,148-66 

7-1 

Pittsburg,  Pa.  ..... 

699-2 

14-33 

Rock  Island,  111  

566-68 

14-40 

St.  Louis,  Mo.  .       .       .  . 

429-29 

14-17 

Terre  Haute,  Ind.    .       .       .  . 

485-55 

14-44 

THE   ENGINEER'S  HANDY-BOOK. 


499 


TABLE 


SHOWING  THE  FORCE  OF  THE  WIND  IN  POUNDS  PER  SQUARE  FOOT  AT 
DIFFERENT  VELOCITIES. 


Miles 

PER 

Hour. 

Feet  per 
Second. 

Force  per 
Square  Foot 
Pound. 

1 

1-47 

0-005 

Hardly  perceptible. 

2 
3 

2-93 
4-4 

0-020 
0-044 

>  Just  perceptible. 

4 

5-87 

0-079 

5 
6 

7-  33 

8-  8 

0-123 
0-177 

1 

[^Gentle,  pleasant  wind. 

7 

10-25 

0-241 

1 

8 

11-75 

0-315 

9 

13-2 

0-400 

10 

14-67 

0-492 

12 

17-6 

0-708 

^Pleasant,  brisk  gales. 

14 

20-5 

0-964 

15 

22-00 

1-107 

16 

23-45 

1-25 

18 

26-4 

1-55 

20 

29-34 

1-968 

-  Very  brisk. 

25 

36-67 

3-075 

30 

44-01 

4-429 

35 

51-34 

6-027 

-  High  wind. 

40 

58-68 

7-873 

45 

6601 

9-963 

50 

73-35 

12-30 

•  Very  high. 

55 

80-7 

14-9 

60 
65 

88-02 
95-4 

17-71 
20-85 

j 

►  Storm  or  tempest. 

70 

102-5 

24-1 

Great  storm. 

75 
80 

110- 
117-36 

27-7 
31-49 

1  Hurricane. 

100 

146-66 

50- 

Tornado. 

Horse-Power  of  Wind  Storms. 

It  is  asserted  that  severe  wind  storms  exert  a  pressure  of  from 
25  to  30  lbs.  per  square  foot,  and  travel  from  50  to  70  miles  per 


500 


THE   ENGINEER'S  HANDY-BOOK. 


hour.  Assuming  that  the  pressure  is  30  lbs.  per  square  foot,  or 
^  of  a  pound  per  square  inch,  with  a  speed  of  66  miles  per  hour, 
then,  as  there  are  27,878,400  square  feet,  or  4,014,489,600  square 
inches  in  a  square  mile,  if  the  pressure  of  the  storm  was  exerted 
for  the  height  of  half  a  mile,  it  will  give  an  area  of  2,007,244,800 
square  inches  for  each  mile  in  width  upon  which  the  storm  acts. 

Rule  for  finding  the  horse-power  of  wind  storms. 

Multiply  the  area  acted  on  in  inches  by  the  pressure  in  lbs.  per 
square  inch ;  then  multiply  this  product  by  the  speed  in  feet  per 
minute,  and  divide  by  33,000.  The  quotient  will  be  the  horse- 
power of  the  storm. 

Example.  —  2,007,244,800  square  inches  x  1*5  lbs.  pressure  X 
5800  feet  -r-  33,000,  which  gives  as  a  result  70,557,700  horse- 
power developed  for  each  mile  of  breadth  of  the  track  of  the  storm. 
To  produce  the  same  horse-power  with  improved  engines  consum- 
ing but  two  pounds  of  coal  per  hour  per  horse-power,  would  re- 
quire 63,000  gross  tons  of  coal. 

Altitude  of  the  Highest  Mountains  in  the  World. 

The  highest  peak  of  the  Himalayas,  in  Asia,  is  25,659  feet 
above  sea-level. 

Mont  Blanc,  the  highest  peak  of  the  Alps,  is  15,732  feet. 

The  highest  peak  of  the  Andes  is  14,760  feet. 

The  peak  of  Teneriffe  is  11,454  feet. 

Mount  /Etna  is  9,000  feet. 

The  highest  point  in  the  Pyrenees  is  8,400  feet. 

The  highest  inhabitable  point  on  the  globe  is  Ancomarsa,  one 
of  the  Peruvian  Andes,  which  is  16,000  feet. 

Highest  Waterfalls  in  the  World. 

The  Ribbon  Falls,  Yosemite  Valley,  U.  S.  A.,  3,300  feet. 

Yosemite  Falls,  U.  S.  A.,  2,600  feet. 

The  Arve  Falls,  Bavaria,  Europe,  2,000  feet. 

The  Falls  of  Montmorency,  Canada,  250  feet. 

Niagara  Falls,  United  States,  158  feet. 


THE   ENGINEER\s    HANDY-BOOK.  501 

T  A  J3  I.  E 


SHOWING  THE  RELATIVE  VOLUMES  OF  AIR  AT  VARIOUS  TEMPERATURES. 


Temp. 
Fah. " 

Volume  in 
Cubic  In. 

Temp, 
Fah. 

Volume  in 
Cubic  In. 

Temp. 
Fah. 

Volume  in 
Cubic  In. 

Temp 
Fah. 

Volume  in 
Cubic  In. 

—49 

834*7 

—  6 

922*5 

37 

1010*2 

80 

1098*0 

—48 

836*7 

—  5 

924*5 

38 

1012*2 

81 

1099*0 

—47 

838*8 

—  4 

926*5 

39 

1014*3 

82 

1100*0 

—46 

840*8 

—  3 

928*6 

40 

1016*3 

83 

1102-1 

—45 

842*8 

—  2 

930*6 

41 

1018*4 

84 

1104-1 

—44 

844*9 

—  1 

932*7 

42 

1020*4 

85 

1106-2 

—43 

846*9 

—  0 

934*7 

43 

1022*4 

86 

1108*2 

—42 

849*0 

1 

936*7 

44 

1024*5 

87 

1110*2 

—41 

851*0 

2 

938*8 

45 

1026*5 

88 

1112*3 

—40 

853*1 

3 

940*8 

46 

1028*6 

89 

1114*3 

—39 

855*1 

4 

942*9 

47 

1030*6 

90 

1116*4 

—38 

857*1 

5 

944*9 

48 

1032*7 

91 

1118*4 

—37 

859*2 

6 

947*0 

49 

1034*7 

92 

1120*4 

—36 

861*2 

7 

949*0 

50 

1036*7 

93 

1122*5 

—35 

863*3 

8 

951*0 

51 

1038*8 

94 

1126*5 

—34 

865*3 

9 

953*1 

52 

1040*8 

95 

1128*6 

—33 

867*3 

10 

955*1 

53 

1042*9 

96 

1130*6 

— 32 

869*4 

11 

957*1 

54 

1044*9 

97 

1132*7 

— 31 

871*4 

12 

959*2 

55 

1046*9 

98 

1134*7 

— 30 

873*5 

13 

961*2 

56 

1049*0 

99 

1136*7 

— 29 

875*5 

14 

963*3 

57 

1051-0 

100 

1138*8 

—28 

877*6 

15 

965*3 

58 

1053*1 

101 

1140*8 

—27 

879*6  . 

16 

967*3 

59 

1055*1 

102 

1142*9 

—26 

881*6 

17 

969*4 

60 

1057*1 

103 

1144*9 

—25 

883*7 

18 

971*4 

61 

1059*2 

104 

11470 

—24 

885*7 

19 

973*5 

62 

1061*2 

105 

1149*0 

— 23 

887*8 

20 

975*5 

63 

1063*3 

106 

1151  *0 

— 22 

889*8 

21 

977*6 

64 

1065*3 

107 

1153*1 

— 21 

891*8 

22 

979*6 

65 

1067*3 

108 

1155*1 

—20 

893*9 

23 

981*6 

66 

1069*4 

109 

1157*1 

— 19 

895*9 

24 

983*7 

67 

1071*4 

110 

1159*2 

— 18 

898*0 

25 

985*7 

68 

1073*5 

111 

1161*2 

—17 

900*0 

26 

987*8 

69 

1075*5  ' 

112 

1163*3 

— 16 

902*0 

27 

989*8 

70 

1077*6 

113 

1165*3 

— 15 

904*1 

28 

991*8 

71 

1079*6 

114 

1167*3 

— 14 

906*1 

29 

993*9 

72 

1081*6 

115 

1169*4 

—13 

908*2 

30 

995*9 

73 

1083*7 

116 

1171*4 

—12 

910*2 

31 

998-0 

74 

1085*7 

117 

1173*5 

—11 

912*2 

32 

1000*0 

75 

1087*8 

118 

1175*5 

—10 

914*3 

33 

1000*2 

76 

1089*8 

119 

1177*6 

—  9 

916*3 

34 

1004*1 

77 

1091*8 

120 

1179*6 

-  8 

918*4 

35 

1006*1 

78 

1093*9 

121 

1181*6 

—  7 

920*4 

36 

1008*2 

79 

1095*9 

122 

1183*7 

502  THE   ENGINEER'S  HANDY-BOOK. 


TABLE— {Continued.) 


Temp. 
Fah. 

Volume  in 
Cubic  In. 

Temp. 
Fah. 

Volume  in 
Cubic  In. 

Temp. 
Fah. 

Volume  in 
Cubic  In. 

Temp. 
Fah. 

Volume  in 
Cubic  In. 

1  '>Q 

lloO  i 

1  ^^9 

lZt4  0 

1  ftO 

1  Q09*0 

90ft 

looy  Z 

1  OA 

1 1  ft7  •  Q 
llo/  o 

100 

1 9AA*Q 

1  ft! 
.  lol 

1  Q04.*1 
lOU^  1 

90Q 

1 QA1 *9 
loDl  Z 

1  Qc; 
iZo 

lloy  o 

1  c:4- 
lO-t 

1 94Q*0 

1  ft9 
lo^ 

1  QOA'1 
louo  1 

91 0 
ZIU 

loDO  0 

iiyi  o 

100 

1  9^^!  *0 

100 

1  QOft'9 
louo  ^ 

91 1 
Zll 

loDO  0 

1  97 

1 1QQ'Q 

100 

1  9'=i^*0 

1ft4. 
lot 

1  ^10*9 
lOlU  ^ 

919 

1 ^A7*^ 
100 1  0 

iiyo  u 

1  ^1 

l^OO  1 

Ift^ 
100 

1  m  9*9 

lOlZi  ^1 

91  Q 
^lo 

1  ^AQ*4. 

lOUt/  t 

1  9Q 

llfo  u 

100 

19^^7*1 

IftA 

lOU 

1  ^^A*^ 

lOlt  0 

914. 
Zlt 

1  ^71  '4. 
10/ 1  t 

1  Qn 

1 9nn'n 
izuu  u 

1  ft7 

l04 

1  Q1  A*Q 
lOlD  0 

91  CI 
ZIO 

10  /  o  0 

1  Ql 
lol 

1  AO 
IDU 

1 9A1 '9 
l^Ol  .^j 

Iftft 

loo 

1  *^1ft*4. 
1010  t 

91 A 
ZIO 

10  1  0  0 

1  Q9 

1 9nA*i 

IZlUt  1 

1 A1 

1 9AQ*Q 

IftQ 

1  ^90*4. 

91  7 
Zl  i 

10  I/O 

1  QQ 

li>i> 

IZUD  1 

1  A9 

1  9Af\*Q 

IQO 

1  ^99*4. 

lO^Zi  t 

91  ft 
Zlo 

1 ^7Q*A 

IDo 

1 9A7*Q 

1Q1 

lO^t  0 

910 
Ziy 

1  ^ftl  'A 
lool  0 

ioO 

1  (\1 

lot 

1  9AQ*A 

izoy  t 

1Q9 

1  ^9A*'^ 

990 

1  ^ftQ*7 
looo  / 

loO 

-1  o-i  9.9 

100 

1 971 'A 

i-At  1  t 

IvO 

1 ^9ft*A 
loZo  0 

9QO 
ZOU 

14.04.*1 
ItUt  1 

1914.'^ 

1  Afi 

1 97^*^ 

1Q4. 

IcJt 

1 ^^O'A 
loou  0 

940 

14.94.*£; 
it^t  0 

loo 

i^io  0 

1  (\7 
1D< 

1 97^*^ 

lOOZi  0 

9'^0 

Ittt  »7 

lou 

1 91  Q»4. 

l^lo  rt 

1  Aft 
IDo 

1 977*^ 

1QA 

loot  1 

9AO 
ZOU 

ItOu  0 

1 990*4. 

1 AQ 
10  a 

1 97Q*A 

IZi  1  t7  0 

1Q7 

1 Q^A*7 
1000  / 

970 
Z/U 

14ft^*7 
itoo  / 

14:1 

1 999*4. 

1  70 
1  /U 

1  9ft  1  'A 

IQft 

1  tlQft'ft 
looo  0 

9QO 
ZoU 

lOUD  1 

14.9 

1  994.* '^i 

1  71 
1/1 

1  9ftQ*7 

1QQ 

1  Q4.0*ft 
lotU  0 

900 

zyu 

1  '^9A*f^ 
lOZD  0 

179 

1  i  jU 

1 9ft.^*7 

900 

1  ^49*Q 

•lot^j  u 

OOU 

1 ^4A*Q 

lOtD  iJ 

14.4. 

lit 

1 99ft 'fi 

17^ 

19ft7*ft 

901 

1  ^44.*Q 
lott  0 

1 7'^1  *0 
1  /  01  U 

1 

ItO 

1 9^0*  A 

1 7A 
1 

1  9ftQ  •  Q 

909 

loto  V 

C\00 

iQc;c;*i 
lyoo  1 

146 

1232-7 

175 

1291-8 

203 

1349-0 

600 

2159-2 

147 

1234-7 

176 

1293-9 

204 

1351-0 

700 

2363-3 

148 

1236-7 

177 

1295-9 

205 

1353-1 

800 

2567-4 

149 

1238-8 

178 

1298-0 

206 

1355-1 

900 

2771-5 

150 

1240-8 

179 

1300-0 

207 

1357-1 

1000 

2975-6 

151 

1242-9 

Technical  Terms  which  are  Applied  to  Fluids  and  Vapors, 
and  which  Bear  a  Certain  Relation  to  the  Steam-Engine. 

Vaporization. — Vaporization  is  the  act  or  process  of  vaporizing 
liquids,  or  converting  them  into  vapor. 

Diffusion  of  vapor. —  Diffusion  of  vapor  means  the  state  of 
being  scattered,  as  steam  on  escaping  from  the  mouth  of  an  ex- 
haust-pipe is  wafted  away  and  scattered  over  a  great  extent  of 
space. 


THE   ENGINEER\s  HANDY-BOOK. 


503 


Compressibility  means  the  quality  of  being  compressible  or 
being  capable  of  being  compressed  into  a  smaller  space,  while  in- 
compressibility  implies  the  opposite  property.  ^ 

Conductibility  means  the  quality  of  being  conductible,  that  is, 
of  being  capable  of  being  conducted  or  conveyed  away. 

Expansion  means  the  state  of  being  expanded  or  being  capable 
of  expanding,  either  in  surface  or  bulk. 

Boiling-point  means  the  temperature  at  which  fresh  water  will 
boil  at  sea-level,  which  is  generally  understood  to  be  212°  Fah. 

Ebullition  is  the  motion  produced  in  a  liquid  by  the  rapid  con- 
version of  a  part  of  it  into  vapor  by  the  application  of  heat. 

Condensation  means  the  process  of  converting  vapors  into  fluids 
by  the  abstraction  of  a  portion  of  their  heat  mechanically. 

Evaporation  is  a  term  applied  to  all  bodies  existing  in  an  aeri- 
form state ;  while  spontaneous  evaporation  means  the  natural  ten- 
dency inherent  in  all  fluids  to  evaporate. 

Fuel. 

The  word  fuel  is  used  to  denote  substances  which  may  be  burned 
by  means  of  atmospheric  air  with  sufficient  rapidity  to  evolve  heat 
capable  of  being  applied  to  economical  purposes.  Fuel  consists 
either  of  vegetable  matter  or  of  the  products  of  the  natural  or 
artificial  decomposition  of  such  matter.  Vegetable  matter,  which 
consists  principally  of  woody  tissue,  is  composed  of  carbon,  hy- 
drogen and  oxygen,  comprising  the  organic  part,  and  a  small  pro- 
portion of  so-called  earthy  matter,  that  which  is  inorganic.  The 
sun  is  the  source  of  the  heat-producing  power  of  fuel,  since  the 
organic  parts  are  derived  from  water,  and,  except  in  particular 
cases,  from  the  carbonic  acid  of  the  atmosphere,  which  are  decom- 
posed in  the  economy  of  plants  by  the  action  of  solar  light. 


504 


THE   ENGINEER\s  HANDY-BOOK. 


Hydrogen  in  fuel  must  always  be  in  association  with  carbon,  but 
carbon  practically  free  from  hydrogen  may  be  procured  abun- 
dantly and  applied  as  fuel.  In  all  fuel  containing  carbon,  hydrogen, 
and  oxygen,  the  proportion  of  hydrogen  may  be  equal  to  or  greater, 
but  never  less,  than  that  required  to  form  water  with  the  oxygen. 
It  is  only  the  hydrogen  in  excess  of  this  which  is  available  as  a 
source  of  heat,  so  that,  in  the  combustion  of  a  substance  whose 
composition  is  represented  by  carbon  and  water,  the  carbon  alone 
is  the  source  of  heat.  The  hydrogen  existing  in  combination  with 
oxygen  in  the  state  of  water,  so  far  from  contributing  to  the  actual 
amount  of  heat  produced,  must  be  evaporated  at  the  expense  of 
the  heat  developed  by  the  combustion  of  the  carbon. 

If  we  compare  different  fuels,  and  assign  them  a  value  for  heat- 
ing purposes  based  on  their  chemical  constitution,  we  will  find 
that  petroleum  is  about  25  per  cent,  superior  to  all  others  theoret- 
ically ;  in  round  numbers,  it  is  capable  of  evaporating  15  lbs.  of 
water  per  pound  of  fuel,  while  a  pound  of  anthracite  coal  can 
evaporate  11  lbs.,  and  a  pound  of  coke  only  about  9  lbs.;  these 
figures  varying,  to  a  certain  extent,  with  the  diflerent  qualities  of 
the  fuels. 

The  chemical  properties  of  coal  are,  free  carbon,  hydro-carbons, 
water  or  oxygen,  and  hydrogen,  with  solid  matter  termed  ash  ;  the 
proportions  of  these  vary  considerably.  In  some  instances,  the 
solid  matter  is  25  per  cent.,  w^hile  with  superior  coal,  only  6  or  10 
per  cent.  The  products  of  combustion  are  carbonic  acid  gas,  ni- 
trogen, air,  ashes,  and  steam. 

The  oxygen  necessary  for  the  combustion  of  coal  is  derived 
from  the  atmosphere.  One  pound  of  carbon  in  combustion  unites 
with  2*66  lbs.  of  oxygen,  and  the  product  is  3*66  lbs.  of  carbonic 
acid  gas.  From  the  above  it  will  be  seen  that  to  the  2*66  lbs. 
of  oxygen  11  lbs.  of  air  would  have  to  be  brought  into  contact 
with  the  pound  of  coal  (if  pure  carbon)  to  render  its  combustion 
complete ;  but,  as  coal  contains  hydrogen,  it  is  found  that  instead 
of  11,  12  lbs.  are  required. 

The  value  of  wood  as  fuel  compared  with  coal. — Two  and  a 


THE   ENGINEER\s  HANDY-BOOK. 


505 


half  pounds  of  dry  wood  are  equal  to  one  pound  (average  quality) 
of  soft  coal,  and  the  fuel  value  of  the  same  weight  of  different 
woods  is  very  nearly  the  same,  —  that  is,  a  pound  of  hickory  is 
worth  no  more  for  fuel  than  a  pound  of  pine,  assuming  both  to 
be  dry.  If  the  value  be  measured  by  the  weight,  it  is  important 
that  the  wood  be  dry,  as  each  10  per  cent,  of  moisture  or  water 
in  the  wood  will  detract  about  12  per  cent,  from  its  value  as  a 
fuel. 

The  weight  of  one  cord  of  different  woods  (air-dried)  is  as 


follows : 

Hickory,  or  Hard  Maple    ......    4500  lbs. 

White  Oak   3850  " 

Beech,  Red  Oak,  and  Black  Oak       ....    3250  " 

Poplar,  Chestnut,  and  Elm   2350  " 

Pine   2000  " 

The  fuel  value  of  wood,  as  compared  with  coal,  is  about  as 
follows : 

1  Cord  air-dried  Hickory,  or  Hard  Maple,  equal  to  2000  lbs.  coal. 
1  Cord  air-dried  White  Oak  equal  to  .       .       .    1725  " 
1  Cord  air-dried  Beech,  Red  Oak,  or  Black  Oak 

equal  to   1450  "  " 


1  Cord  air-dried  Poplar,  Chestnut,  or  Elm  equal  to    1050  " 


1  Cord  air-dried  Average  of  Pine  Wood  equal  to     925  " 


Comparative  value 

of  different  Icinds  of  wood  for  fuel. 

Shellbark  Hickory  . 

.    .  100 

Yellow  Oak  

60 

Piguut  Hickory  .  . 

.    .    95  i 

Hard  Maple  

59 

White  Oak    .    .  . 

.    .  84 

White  Elm  

58 

White  Ash     .    .  . 

.    .  77 

Red  Cedar  

56 

Dog- Wood.    .    .  . 

.    .  75 

Wild  Cherry  

55 

Scrub  Oak .... 

.    .  73 

Yellow  Piue  

54 

White  Hazel  .    .  . 

.    .  72 

52 

Apple-Tree     .    .  . 

.    .  70 

Yellow  Poplar  .... 

51 

Red  Oak    .    .    .  . 

.    .  67 

Butternut     and  White 

White  Beech  .    .  . 

.    .  65 

1  Birch  

43 

Black  Birch  .    .  . 

.    .  62 

1  White  Piue  

30 

43 


506 


THE   engineer's  HANDY-BOOK. 


Fire.  — Fire  is  one  of  the  oldest  chemical  phenomeDa.  Its  dis- 
covery was  one  of  the  greatest  boons  conferred  on  mankind,  as 
with  it  arose  sociability,  the  family  joys  of  the  domestic  hearth, 
all  industries  and  arts,  together  with  the  wonders  they  have  pro- 
duced, and  still  produce  from  day  to  day.  Henoe,  we  can  readily 
understand  how  it  is  that  fire  has  ever  been,  and  still  is,  among 
nations  the  object  of  a  special  worship  (priests  of  Baal,  Gebers, 
Hindoos,  Brahmans,  etc.),  and  has  often  Sgareii  In  the  religious 
or  funereal  rites  of  nations  most  remote  from  each  other,  both 
in  time  and  space,  as  the  Chaldees,  Hebrews,  Greeks,  Romans, 
Peruvians,  Mexicans,  etc.  But  how  and  when  this  great  discovery 
was  made,  in  the  absence  of  which  we  can  hardly  conceive  of  the 
possibility  of  human  arts,  or  even  of  human  existence,  is  un- 
known. 

Flame.  — Flame  is  gas  or  vapor,  of  which  the  surface,  in  con- 
tact with  the  atmospheric  air,  or  other  supporter  of  combustion, 
burns  with  the  emission  of  light.  The  luminosity  of  flame  is 
generally  admitted  to  be  caused  by  the  presence  of  particles  of 
solid  matter  within,  or  in  immediate  contact  with,  the  gas  in  active 
combustion. 

Smoke.  —  Smoke  is  the  product  of  imperfect  combustion,  caused 
either  by  a  want  of  oxygen  or  a  want  of  temperature.  Bitu- 
minous coal  contains  from  5  to  6  per  cent,  of  hydrogen,  which 
unites  with  the  oxygen  necessary  to  combustion,  and  constitutes 
water.  A  ton  of  bituminous  coal  will  make  nearly  one-third  of 
a  ton  of  water  in  the  form  of  steam.  That  this  steam  is  black, 
does  not  necessarily  indicate  the  presence  of  much  carbon,  as  a 
grain  of  soot,  if  distributed  evenly  in  fine  particles  through  a 
cubic  foot  of  steam,  would  color  it  blacker  than  the  ace  of  spades. 

Chemical  analysis  proves  the  basis  of  soft  coal  to  be  carburetted 
hydrogen,  but  it  generally  contains  benzole,  naphtha,  asphaltum, 
paraffine,  lubricating  oil,  and  a  great  variety  of  other  substances 
used  in  the  mechanical  arts. 


THE   engineer's  HANDY-BOOK. 


507 


Heat. 

According  to  the  dynamical  or  mechanical  theory,  heat  is  the 
result  of  motion  among  the  atoms  of  matter,  or,  as  it  may  be 
otherwise  stated,  of  inter-atomic  movement;  and  this  motion  is 
capable  of  being  propagated  through  space,  from  one  body  to 
another,  by  undulations  of  a  so-called  ether  assumed  to  be  every- 
where existent  in  the  universe. 

The  relative  effect  of  such  heat  producing  motion,  or,  in  other 
words,  the  relative  proportions  of  heat  required  to  cause  given 
effects,  may  be  accurately  indicated  by  numbers,  just  as  if  heat 
were  a  ponderable  agent ;  and  it  is  usual  to  speak  of  heat  as  if  it 
were  an  independent  material  substance  :  thus,  it  is  said  to  be 
evolved,  or  emitted,  radiated,  conducted,  absorbed,  and  stored  up, 
or  accumulated.  As  a  variable  amount  of  the  heat  evolved  in 
the  combustion  of  a  body  is  absorbed  in  the  work  of  effecting 
alterations  in  the  physical  condition  of  the  combustible  elements 
necessary  to  their  effective  oxidation^  it  is  impossible  to  estimate 
the  absolute  quantity  of  heat  evolved  by  the  combustion  of  a 
body ;  yet  the  relative  quantities  of  heat  evolved  by  the  com- 
bustion of  different  bodies  which  may  be  utilized,  can  be  accurately 
determined. 

One  of  the  remarkable  efTects  of  the  application  of  heat  to 
matter  is,  that  the  same  amount  will  affect  equal  weights  of  dis- 
similar kinds  in  different  degrees.  Thus,  the  amount  of  heat  that 
will  raise  1  lb.  of  water  from  100°  to  200°  Fah,  will  raise  30  lbs. 
of  mercury  through  the  same  range.  The  amount  that  will  raise 
1  lb.  of  water  1°,  will  raise  14  lbs.  of  air. 

The  capacity  of  a  body  for  heat  is  termed  its  specific  heat,  and 
may  be  defined  as  the  number  of  units  of  heat  necessary  to  raise 
the  temperature  of  1  lb.  of  that  body  1°  Fah. 

The  thermal  unit,  or  unit  of  heat,  as  it  is  termed,  is  the  quan- 
tity of  heat  that  v»^ill  raise  1  lb.  of  pure  water  1°  Fah.,  or  from 
39°  to  40°  Fah. 

The  term  latent  heat  means  the  quantity  of  heat  which  has  dis' 


508  THE    ENGINEER'S  HANDY-BOOK. 


appeared  from  a  body,  owing  to  an  increase  of  temperature.  The 
sensible  heat  is  that  which  is  sensible  to  the  touch  or  measurable 
by  the  thermometer. 

The  mechanical  equivalent  of  heat  is  the  amount  of  work  per- 
formed by  the  conversion  of  one  unit  of  heat  into  work,  and  the 
mechanical  theory  heat  is  based  on  the  assumption  that  heat  and 
work  are  mutually  convertible. 

TABLE 

SHOWING  THE  LATENT  HEAT  OF  VARIOUS  SUBSTANCES. 


Fah. 

Ice  140° 

Sulphur    .       .       .       .  .144 

Lead  162 

Beeswax  176 

Zinc  493 


Fah. 

Steam   990° 

Vinegar  875 

Ammonia  ....  860 
Alcohol  .  .  .  •.  .442 
Ether  301 


TABLE 


SHOWING  THE  RADIATING  PROPERTIES  OF  DIFFERENT  SUBSTANCES. 


Water 

Fah. 
.  100° 

Blackened  Tin .       .       .  . 

Lampblack 

.  .100 

Clean  Tin        .       .       .  . 

Writing-Paper  . 

.  100 

Scraped  Tin     .       .       .  , 

Glass 

.  90 

India-Ink  . 

.  88 

Bright  Lead 

.  19 

Polished  Iron  .       .       .  . 

Silver 

.  12 

Fah. 

100° 
12 
16 
85 
20 
15 
12 


TABLE 


SHOWING  THE  EFFECTS  OF  HEAT  UPON  DIFFERENT  BODIES. 


Cast  Iron  thoroughly  smelted 
Fine  Gold  melts  at 
Fine  Silver  " 
Copper  " 
Brass 
Zinc 

Quicksilver  boils  at 
Linseed  Oil  " 


Fah. 
2,754^ 

1,983 
1,850 
2,160 
1,900 
740 
630 
600 


Lead  melts  at  . 
Bismuth  " 
Tin 

Tin  and  Bismuth, 

equal  parts 
Alcohol  boils  at 
Ether 

Mercury  melts  at 


melt  at 


Fah 
594^ 

476 

421 

283 

174 
98 
39 


THE   engineer's  HANDY-BOOK. 


509 


TABLE 

SHOWING  THE  SPECIFIC  HEAT  OF  DIFFERENT  SUBSTANCES. 


SOLIDS. 


00951 

0-0939 

Gold  

0-0324 

Glass 

0-1977 

0-1138 

Ice    .  . 

0-5040 

0-0314 

Sulphur . 

0-2020 

Platinum  

0-0324 

Charcoal 

0-2410 

Silver  ...... 

0-0570 

Alumina 

0-1970 

Tin    ......  . 

0-0562 

Stones,  Bricks,  etc.,  about  0-2200 

0-0955 

LIQUIDS. 

Water  ..... 

1-0000 

Mercury. 

0-0332 

Lead  (melted)     .  . 

0-0402 

Alcohol  . 

06150 

feulpnur 

0-2340 

Fusel  Oil 

0-5640 

Bismuth  "  ... 

0-0363 

Benzine  . 

0-4500 

Tin         "      .    .    .  . 

0-0637 

Ether  . 

0  5034 

TABLE 

SHOWING  THE  RELATIVE 

WEIGHT  AND  VOLUME 

OF  DIFFERENT 

GASES. 

Air     .       .       .  . 

0-238    .  . 

0-169 

Oxygen 

0-218    .  . 

0-156 

Hydrogen  . 

3-405    .  . 

2-410 

Steam  Gas  . 

0-480    .  . 

0-346 

Carbonic  Acid  Gas 

0-217    .  . 

Nitrogen 

0-244    .  . 

Olefiant  Gas 

0-404    .  . 

0-173 

Carbonic  Oxide  . 

0-245    .  . 

0-237 

Ammonia 

0-508    .  . 

0-299 

43^ 


510 


THE   engineer's  HANDY-BOOK. 


TABLE 

SHOWING  THE  NON-CONDUCTING  PROPERTIES  OF  DIFFERENT  MATERIALS 


AT  EVEN  THICKNESS. 

Black  Slate   100 

Sandstone  .........  71*95 

Fire-Brick  .   61-70 

Soft  Chalk   56 

Asphaltum   45 

Oak  Wood   33*66 

Pine  Wood   27*61 

Wood  and  Plaster   25*55 

Sulphate  of  Lime   20*26 

Sulphate  of  Lime  and  Sand   18*70 

Coarse  Ashes,  Shavings,  Hay,  and  Straw    .       .       .  25-85 

Sawdust  and  Tan-Bark  (fine)   17-20 

Mineral  Wood  of  Asbestos,  cemented  ....  18-20 

Fine  Asbestos,  in  thread   13-15 

Fine-Powdered  Charcoal   14-16 

Ordinary  Mineral  Wool,  Hair-Felt,  Cat-Tail,  etc.      .  10-13 

Extra  Mineral  Wool,  Raw  Silk,  Cotton,  etc.,  quite  loose  8-10 

Ice   0 


Cooling  of  liquids  and  solids. —  The  velocities  with  which  a 
solid  body  cools  in  a  liquid  are  approximately  the  same,  whether 
it  be  placed  near  the  surface  or  near  the  bottom.  It  is  slightly 
less  when  the  body  is  brought  immediately  under  the  surface. 
The  nature  of  the  external  surface  of  the  cooling  body  has  but 
little  influence.  The  velocity  of  cooling  increases  very  consider- 
ably for  the  same  body  immersed  in  the  same  liquid  with  increas- 
ing temperature  of  the  latter.  If  the  cooling  power  of  water  be 
taken  at  1,  that  of  alcohol  is  equal  to  0*58;  mercury,  2*07;  sul- 
phate of  copper,  1*03,  and  common  salt,  1*05. 

Combustion. 

Combustion  is  a  subject  of  interest  to  the  engineer,  manufac- 
turer, and  individual,  and  must  ever  continue  to  be  so,  while  the 


THE  engineer\s  IIANDY-BOOK.  511 

steam-engine  is  used  as  a  motive  power,  and  so  long  as  artificial 
heat  is  employed  for  manufacturing  and  domestic  purposes,  as 
well  as  for  the  preservation  of  animal  life.  This  subject  has  not 
heretofore  received  that  consideration  which  its  importance  in  an 
economical  point  of  view  so  eminently  deserves.  This  arose,  in 
part,  from  the  lavish  hand  with  which  a  bountiful  Nature  has  sup- 
plied us  with  minerals,  woods,  and  cereals,  and  the  cl6se  prox- 
imity of  the  source  of  supply  to  the  avenue  of  demand  ;  but  the 
increase  of  population  and  demand,  and  the  diminution  in  supply, 
are  making  the  examination  of  the  subject  an  imperative  neces- 
sity. It  is  quite  common  to  see  in  the  neighborhood  of  manu- 
facturing establishments,  and  even  households,  splendid  lumps  of 
the  finest  qualities  of  anthracite  coal,  nearly  pure  carbon,  lying  in 
the  highway,  to  be  forced  into  the  ground  by  the  pressure  of  hoof 
or  wheel,  and  after  rain  storms  dumping-grounds  glisten  with 
kernels  of  coal  that  have  never  been  exposed  to  the  fire,  which 
are  as  fine  as,  and  in  many  respects  superior  to,  that  which  has  been 
placed  in  the  furnace.  The  same  thing  may  be  said  of  oil,  cotton- 
waste,  piston-rod  packing,  etc. ;  but,  as  the  cost  of  material  has  to 
be  paid  out  of  the  profits  of  production,  such  carelessness  is  gen- 
erally followed  by  retributive  justice;  and  the  old  adage  which 
says  "  that  a  wilful  waste  is  generally  followed  by  a  woeful  want," 
is  sooner  or  later  realized. 

Combustion  is  the  result  of  chemical  alterations  of  a  violent 
character,  and  the  heat  thus  evolved  is  merely  an  incidental  phe- 
nomenon, or  a  vehement  combination  of  various  materials.  In 
combustion,  the  carbon  and  oxygen  have  so  great  a  chemical  af- 
finity for  each  other,  that  they  rush  violently  together,  and  by  the 
force  of  their  combustion  produce  instant  heat. 

The  composition  of  anthracite  coal  of  the  best  quality  is  as 
follows:  carbon,  90*45;  hydrogen,  2-43;  oxygen,  2*45,  and  ashes 
4*67,  with  a  minute  quantity  of  nitrogen.  When  coal  is  heated,  it 
discharges  its  gas ;  the  solid  carbon  then  ignites  in  presence  of 
oxygen,  and  retains  the  temperature  necessary  for  combustion  as 
long  as  the  necessary  quantity  of  oxygen  is  applied.    The  average 


512 


THE   ENGI^fEER^S  HANDY-BOOK. 


weight  of  anthracite  coal  is  about  53  lbs.  per  cubic  foot,  and  the 
number  of  cubic  feet  per  ton  will  average  about  42'3. 

Bituminous  coal  is  a  compound  substance.  A  ton  (2000  lbs.)  con- 
tains about  1600  lbs.  or  80  per  cent,  of  carbon ;  100  lbs.  or  5  per 
cent,  of  hydrogen ;  and  300  lbs.  or  15  per  cent,  of  oxygen,  ni- 
trogen, sulphur,  and  ashes.  The  weight  of  bituminous  coal  will 
average  about  50  lbs.  per  cubic  foot  and  44*8  cubic  feet  to  the 
ton,  and  in  the  process  of  coking  it  loses  35  per  cent,  of  its  orig- 
inal weight. 

TABLE 


SHOWING  THE  TOTAL  HEAT  OF  COMBUSTION  OF  VARIOUS  FUELS. 


Sort  of  Fuel. 

Equivalent 

IN  PUBE 

Cabbon. 

Lbs.  of  Water 
Evaporated 
FROM  212°  Fah. 

Lbs.  of  Water 
Raised 
1°  Fah. 

Anthracite  coal  . 

1-05 

15-75 

15225 

Bituminous  "  . 

1-06 

15-90 

15370 

Coke  .... 

0-94 

14-00 

13620 

Charcoal  .    .  . 

0-93 

14-00 

13500 

Dry  wood .    .  . 

0-50 

7-50 

7000 

Spontaneous  combustion. —  This  mysterious  phenomenon  has 
attracted  at  different  times  the  attention  of  chemists  and  philos- 
ophers, and  many  theories  have  been  advanced  to  account  for  its 
development.  Galletly,  who  investigated  the  subject,  found  that 
cotton-waste  soaked  in  boiled  linseed-oil,  and  wrung  out,  if  exposed 
to  a  temperature  of  170°,  set  up  oxidation  so  rapidly  as  to  cause 
actual  combustion  in  105  minutes.  Coleman  also  instituted  a  very 
extensive  series  of  experiments  upon  fragments  of  cotton,  linen, 
jute,  and  woollen  waste  saturated  with  oils  of  different  natures. 

The  theory  which  attributes  spontaneous  combustion  to  the 
presence  of  pyrites  in  the  coal,  may  partially  account  for  the 
increased  number  of  fires ;  but  Richter  has  shown  that,  for  va- 
rious coals  experimented  upon,  those  which  contained  the  most 


THE   engineer's  HANDY-BOOK. 


513 


pyrites  were  not  the  most  subject  to  spontaneous  combustion. 
According  to  him,  air  is  rapidly  absorbed  by  the  coal,  and  the 
oxygen  of  the  air  then  combines  with  the  organic  components  to 
produce  carbonic  acid  and  develop  heat.  According  to  all  prob- 
abilities, however,  the  heat  which  determined  the  spontaneous 
combustion  is  due  both  to  the  oxidation  of  the  iron  and  to  that 
of  the  carbonized  matters.  This  confined  in  badly-ventilated  holds 
speedily  reaches  a  temperature  sufficiently  high  to  produce  com- 
bustion. 

That  most  of  the  bituminous  coals  (English  and  American)  are 
subject  to  spontaneous  combustion  when  in  bulk,  and  under  favor- 
able circumstances,  has  long  been  known.  Experiments  by  Green- 
araann  have  also  proved  conclusively  that  an  exposure  of  bitu- 
minous coal  in  heaps  to  the  action  of  the  weather  for  a  period 
varying  from  two  weeks  to  a  year  results  in  a  large  percentage  of 
loss.  This  loss  is  in  the  nature  of  a  slow  or  incomplete  combus- 
tion; it  is  greater  and  more  rapid  in  large  heaps  than  in  small, 
and  is  also  favored  by  the  greater  or  less  state  of  subdivision  of 
the  coal,  large  fragments  losing  proportionably  less  than  smaller 
ones.    The  loss  varies  from  5  to  25  per  cent. 

The  higher  the  temperature  the  more  rapid  is  the  combustion. 
The  heat  around  the  coal-bunkers  of  steamships  must  necessarily 
be  very  great,  from  their  close  proximity  to  the  boilers  aud  fur- 
naces; and  in  sailing-ships  containing  large  quantities  of  these 
coals  in  bulk,  taken  on  board  mostly  wet,  the  generation  of  heat 
to  the  point  of  ignition  seems  to  be  only  a  question  of  time.  The 
sulphur  and  volatile  matter  in  bituminous  and  hydrogenous  coals 
are  the  active  agents  in  spontaneous  combustion,  and  the  finer  the 
particles  the  more  favorable  is  the  condition  for  producing  that 
result.  The  large  number  of  disasters,  which  have  occurred  from 
the  spontaneous  combustion  of  bituminous  coals  on  board  of  steam- 
ships and  sailing-vessels,  has  called  public  attention  to  the  matter. 
Although  the  manner  by  which  bituminous  coal  stored  in  vessels 
becomes  ignited  is  not  yet  determined,  it  has  been  demonstrated 
that  the  conditions  for  the  \vork  of  spontaneous  combustion  exist 

2H 


514 


THE   ENGINEER'S  HANDY-BOOK. 


wherever  large  bodies  of  bituminous  coal  are  stored  in  close  com- 
partments. 

From  the  foregoing  considerations,  it  would  seem  that,  when 
spontaneous  combustion  takes  place  among  coals  or  other  sub- 
stances, drowning  out  with  water  is  not  always  effective  ;  as,  though 
it  extinguishes  the  fire,  it  leaves  in  the  coal  a  condition  of  things 
very  favorable  to  a  renewed  ignition  at  any  moment.  A  terrible 
explosion  of  coal-gas  recently  occurred  on  board  of  a  steamship  in 
Liverpool,  by  which  fourteen  men  were  injured,  some  of  them 
seriously,  in  consequence  of  a  quantity  of  wet  coal  having  been 
placed  in  the  bunkers  and  the  hatches  closed. 

Water. 

Water,  with  the  barometer  at  30°,  boils  in  the  open  air,  at  sea- 
level,  at  212°  Fah.;  and  in  vacuum,  at  88°  Fah.  The  less  the 
pressure  of  the  atmosphere,  the  lower  is  the  temperature  at  which 
water  will  boil.  The  pressure  of  the  atmosphere  at  sea-level  is 
14*7  lbs.  per  square  inch,  pressing  equally  and  in  all  directions. 
This  has  been  ascertained  from  the  following  illustration.  Because 
the  height  of  a  column  of  air  of  one  square  inch  area  exactly 
balances  a  column  of  mercury  of  the  same  area  30  inches  in 
height,  and  also  a  column  of  water  33*86  feet  in  height,  it  follows 
that  a  column  of  air,  30  inches  of  mercury,  and  33*^86  feet  of  water 
weigh  the  same,  and  since  the  last  two  weigh  respectively  14*7 
lbs.  per  square  inch,  a  full  column  of  air  must  weigh  the  same. 
A  cubic  foot  of  water  evaporated  under  a  pressure  of  one  atmos- 
phere, or  15  lbs.  per  square  inch,  occupies  a  space  of  1700  cubic 
feet. 

Salt  water  boils  at  a  higher  temperature  than  fresh,  owing  to  its 
greater  density,  and  because  the  boiling-point  of  water  is  increased 
by  any  substance  that  enters  into  chemical  combination  with  it. 
Mud  and  other  substances,  so  long  as  they  are  kept  in  mechanical 
solution,  will  not  increase  the  boiling-point  of  water ;  when  these 
substances  settle,  and  burn  to  the  interior  of  the  boilers,  the  boil- 


THE    engineer's  HANDY-BOOK. 


515 


ing-point  will  be  increased.  The  density  of  water  decreases  as  the 
temperature  increases,  since  heat  destroys  cohesion  and  expands 
the  particles,  causing  them  to  occupy  greater  space.  The  power 
of  water  to  hold  chemical  substances,  such  as  salts  of  lime,  in  solu- 
tion, decreases  as  the  temperature  increases ;  from  this  it  follows 
that  boilers  carrying  high-pressure  steam  form  more  scale  than 
those  working  at  low  temperatures. 

The  law  of  expansion  by  heat  and  contraction  by  cold  is  true 
as  relating  to  water,  with  this  exception,  that,  as  hot  water  cools 
down  from  the  boiling-point,  it  contracts  until  45°  Fah.  is  reached, 
but  if  cooled  down  from  this  point  it  expands  again.  The  density 
of  water  decreases  as  the  temperature  increases,  because  water  is 
expanded  into  a  greater  space  by  an  increase  of  temperature.  The 
cohesive  attraction  of  the  particles  is  not  so  great,  and  the  water 
is  therefore  less  buoyant,  thus  allowing  the  hydrometer  to  sink 
lower  than  it  should. 

Water,  like  all  liquids,  expands  by  the  application*  of  heat,  and 
this  fact  alone  shows  the  fallacy  of  the  commonly  accepted  notion 
that  it  is  incompressible ;  the  dilation  and  contraction  of  the  liquid 
is  simply  extension  and  compression  of  its  particles.  Although 
the  expansion  of  water  is  comparatively  slight  between  its  boiling 
and  freezing  points,  yet  it  is  the  most  irregular  of  all  liquids ;  so 
irregular,  in  fact,  that  it  has  been  found  impossible  to  find  a  single 
empirical  formula  to  express  the  expansion  at  different  tempera- 
tures. Below  50°  Fah.  it  is  more  irregular  than  above  that  point, 
as  water  possesses  what  no  other  liquid  has  been  discovered  to 
have,  and  that  is  a  point  of  maximum  density. 

If  we  take  a  water  thermometer  and  expose  it  to  the  cold,  we 
shall  observe  the  following  curious  phenomenon.  The  liquid  will 
gradually  descend  until  it  reaches  the  temperature  of  39*2°  Fah. ; 
at  this  point  the  contraction  will  cease ;  and,  although  the  cold 
acting  on  the  bulb  is  far  below  this  point,  the  liquid  will  gradually 
ascend  until  it  reaches  32°  Fah.,  or  freezing  point,  when  it  will 
solidify.  The  point  at  which  the  liquid  commences  to  ascend  is 
called  its  "  point  of  maximum  density." 


516  THE  engineer's  handy-book. 

One  of  the  most  curious  phenomena  connected  with  water 
before  and  after  freezing,  may  be  demonstrated  as  follows :  Take  a 
tall  jar  and  fill  it  with  water,  say  at  60°  Fah. ;  at  the  top  of  the 
jar  fix  a  small  mercurial  thermometer,  and  another  one  at  the 
bottom  ;  then  place  the  jar  at  rest,  exposed  to  the  cold.  The  lower 
thermometer  will  be  observed  to  fall  more  rapidly  than  the  top 
one,  until  it  reaches  39*2°  Fah.,  when  it  will  remain  stationary. 
The  top  thermometer  will  now  fall,  and  continue  to  do  so  until 
the  water  freezes ;  the  bottom  thermometer  still  remaining  at  39*2° 
Fah.  These  effects  are  easily  explained :  the  particles  of  water 
at  the  top  being  exposed  to  the  cold,  decrease  in  temperature,  thus 
becoming  denser,  and  fall  to  the  bottom,  their  places  being  taken 
up  by  warmer  particles,  which  in  their  turn  undergo  the  same 
change,  until  the  whole  volume  has  completely  circulated,  and 
attained  a  temperature  of  39'2°  Fah.  The  particles  now,  instead 
of  becoming  denser,  actually  expand,  and  so  remain  at  the  top 
until  a  thin  layer  of  ice  is  formed.  This  is  exactly  what  takes 
place  in  our  lakes  and  ponds  during  every  frost ;  the  circulation 
continues  until  the  whole  mass  attains  the  temperature  of  39*2° 
Fah.,  when  it  is  gradually  and  finally  arrested;  a  thin  layer  of 
ice  is  then  formed  at  the  top,  acting  as  a  cloak  to  the  interior, 
which,  remaining  always  at  39*2°  Fah.,  preserves  the  animals  and 
fishes  from  the  action  of  intense  cold. 

Were  it  not  for  this  fact,  our  lakes  and  rivers  would  all  be 
frozen  at  the  bottom,  and,  as  water  is  a  bad  conductor  of  heat, 
they  would  in  time  be  converted  into  a  solid  block  of  ice,  which 
would  defy  the  hottest  rays  of  a  tropical  sun  to  melt.  Thus  we 
see  that  such  a  wise  provision  of  Nature  depends  entirely  on  an 
apparent  exception  to  a  universal  law,  which  is  so  slight  that  it 
requires  the  most  delicate  experiments  to  detect  it.  The  freezing 
point  of  a  liquid  is  almost  invariably  the  same  as  its  melting 
point ;  that  is,  if  we  cool  a  liquid  below  its  melting  point,  it  will 
become  solid.  There  are,  of  course,  many  exceptions  to  this,  and 
even  water  has  been  known  to  be  cooled  down  to  4°  Fah.  without 
freezing.    To  effect  this,  however,  water  most  be  kept  perfectly 


THE   ENGINEER'S    HANDY-BOOK.  517 


still,  as,  with  the  least  vibration,  congelation  commences,  and  the 
temperature  will  instantly  rise  to  zero. 

When  a  substance  solidifies  or  freezes,  there  is  always  a  change 
of  volume,  which  usually  is  a  contraction  ;  but,  in  the  case  of  water, 
an  expansion  takes  place.  The  expansion  of  water  at  the  freezing 
point  is  by  no  means  gradual,  but  takes  place  almost  instantane- 
ously, and  the  amount  of  force  exerted  at  the  time  is  enormous. 
It  has  been  demonstrated  by  actual  experiments,  that  in  freezing, 
water  exerts  a  pressure  of  about  30,000  lbs.  per  square  inch,  which 
far  surpasses  the  strain  that  any  of  our  machinery  could  bear. 

Pure  water  is  composed  of  hydrogen  and  oxygen  in  the  pro- 
portions of  two  measures  of  hydrogen  to  one  of  oxygen,  or  one 
part  of  hydrogen  to  8  of  oxygen ;  or  oxygen,  89  parts  by  weight, 
and  by  measure  1  part;  hydrogen,  by  weight,  11  parts,  and  by 
measure,  2  parts ;  but  pure  water  is  not  attainable,  nor  is  it  to  be 
found  in  the  laboratory  of  the  chemist.  Fortunately,  however, 
pure  water  is  not  necessary,  nor  even  desirable,  for  either  house- 
hold or  manufacturing  purposes ;  because  the  presence  of  air  and 
other  gases  adds  very  materially  to  the  ease  with  which  steam 
may  be  generated,  while  the  ammonia,  which  most  water  contains, 
improves  it  for  manufacturing  purposes. 

The  specific  gravity  of  all  waters  is  not  the  same.  Sea  water 
varies  from  1*0269  to  1*0285,  the  mean  being  1-0277,  thus  requir- 
ing 34*9741  cubic  feet  of  sea  water  to  make  one  ton,  and  about 
35  feet  of  fresh  water.  Water  is  heavier  at  night  than  during  the 
day,  owing  to  the  atmosphere  being  more  dense,  and  the  additional 
weight  of  the  dew. 

Water  has  the  greatest  specific  heat  of  all  known  liquids  ex- 
cept hydrogen,  and  is  therefore  taken  as  the  standard  for  all  solids 
and  fluids.  The  latent  heat  of  water  is  143°  Fah.,  and  that  of 
ice  140°,  as  it  absorbs  that  amount  of  heat  in  changing  from  a 
liquid  to  a  solid  state. 

Water,  under  the  influence  of  heat,  can  be  changed  from  the 
liquid  to  the  gaseous  state  in  two  ways  only,  either  by  conversion 
into  steam,  or  by  decomposition  into  its  constituent  gases,  hydrogep 
44 


518  THE  engineer's  handy-book. 

and  oxygen,  which  decomposition  can  be  effected  only  at  the  ex* 
pense  of  the  apparatus  in  which  it  is  effected. 

TABLE 


SHOWING  THE  QUANTITY  AND  WEIGHT  OF  WATER  IN  PIPES  ONE  FATHOM 
IN  LENGTH  (6  FEET),  AND  OF  DIFFERENT  DIAMETERS  FROM  1  TO  12 
INCHES. 


Diameter 

Quantity  in 

Quantity  in  Im- 

Weight in  Lbs. 

IN  Inches. 

Cubic  Inches. 

perial  Gallons. 

Avoirdupois. 

14-14 

0-051 

0-51 

1 

56-55 

0-205 

2-05 

n 

127-23 

0-460 

4-60 

2 

226-19 

0-818 

8-18 

2i 

353-43 

1-278 

12-78 

3 

508-94 

1-841 

18-41  . 

3J 

692-72 

2-506 

25-06 

4 

904-78 

3-272 

32-72 

4i 

1145-11 

4-142 

41-42 

5 

1413-72 

5-113 

51-13 

5J 

1710-60 

6-187 

61-87 

6 

2035-75 

7-363 

73-63 

6* 

2389-18 

8-641 

86-41 

7 

2770-88 

10-022 

100-22 

7i 

3180-86 

11-505 

115-05  ■ 

O 
O 

QA1  Q-1 1 
oDiy  II 

lo  k)u\j 

loU  o\j 

8i 

4085-64 

u-m 

147-77 

9 

4580-44 

16-567 

165-67 

9i 

5103-52 

18-459 

184-59 

10 

5654-87 

20-453 

204-53 

lOJ 

6234-49 

22-550 

225-50 

11 

6842-39 

24-748 

247-48 

m 

7478-56 

27-049 

270-49 

12 

8143-01 

29-452 

294-52 

m 

8835-74 

38-32 

319-50 

13 

9556-74 

55-3 

34500 

m 

10306-01 

59-6 

373-50 

14 

11083-56 

65-2 

400-50 

THE   ENGINEER'S  HANDY-BOOK. 


519 


TABLE 

SHOWING  THE  QUANTITY  OF  WATER  PER  LINEAL   FOOT  IN   PUMPS,  OR 
VERTICAL  PIPES  OF  DIFFERENT  DIAMETERS. 


Diameter 
of  Pump 
in  Inches. 

Number  of 

Gallons 
per  Lineal 
Foot. 

Number  of 
Cubic  Feet 
per  Lineal 
Foot. 

Diameter 
of  Pump 
in  Inches. 

Number  of 

Gallons 
per  Lineal 
Foot. 

Number  of 
Cubic  Feet 
per  Lineal 
Foot. 

9 

•1  ^fi 

±00 

•091^ 

0 

9^1 7fi 

•179 

•097fi 

9-^14 

•^^71  9 

^  2 

•919 

9-4.^fi 

•^Q40 

•9.'i7 

•041  9 

04 

9-fiO.^ 

\J\J0 

•41 75 

Q 
o 

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ouo 

•n4Qn 

Q 

9-7^4 
z  1  0^ 

•441  7 

•0^7fi 

Z/  fjyJo 

•4fififi 

ttUUU 

0  J 

•41 

•Ofifi^^ 

wUOO 

^•OfiS 
0  uuo 

T:i7ZO 

•47X 

•07f>fi 

o.oqo 

0  LtO  Li 

•51 84 

A 

•.^44 

•0S79 

10 

^•400 

•.54.54 

Arl 

lOi^ 

1 V4 

-O  <J  1  z 

•57*^0 

•1 104 

lOi 
Xv/2 

^•74^ 

0  1  rrO 

•fiOl 

•7fi7 

•1  9^0 

10^ 

Q.QOQ 
0  t7Zt/ 

•fi^09 

•1  ^fi^ 
1000 

1  1 

4-1 14 

^  i  It: 

•fi5QQ 

OtJi/i/ 

.QQ7 

•1 50^ 

111 
±±4 

4-^0^ 

t:  Ov/O 

•fiQ09 

1  •09X 

•1fi4Q 

1  1  fi^ 

4-4Qfi 

•791  9 

1-124 

•1803 

111 

4-694 

•7529 

D 

1  'OO/I 
1  ZZ4 

IZ 

4  oyb 

/  ooo 

6} 

1-328 

•2130 

m 

5-312 

•8521 

6J 

1-436 

•2304 

13 

5^746 

•9217 

61 

1-549 

•2489 

13i 

.  6^196 

•9939 

7 

1-666 

•2672 

14 

6^664 

r0689 

7i 

1-787 

•2866 

15 

7^650 

r2271 

1-912 

•3067 

16 

8^704 

1-3962 

71 

2-042 

•3275 

18 

11016 

1^7670 

One  cubic  foot  of  water  weighs  62i  lbs.,  and  contains  Ih  U.  S. 
gallons. 

One  cubic  foot  of  ice  weighs  57  lbs. 


520  THE  engineer's  handy-book. 


TABLE 

SHOWING  THE  WEIGHT  OF  WATER  AT  DIFFERENT  TEMPERATURES. 


X  HiiYix  jLiixA.  1  U  rvXi^ 

Fah. 

Weight  of  a 
Cubic  Foot 
IN  Lbs. 

T? TVr T> Tf  A  T'TT'RU' 
X  tUM-trcjlxA.  1  U  ixjiif 

Fah. 

Weight  of  a 
Cubic  Foot 
IN  Lbs. 

40° 

62-408 

172° 

60-72 

42° 

62-406 

182° 

60-55 

52° 

62-377 

192° 

60-28 

62° 

62-321 

202° 

60-05 

72° 

62-025 

212° 

59-82 

82° 

62015 

230° 

59-37 

92° 

62-004 

250° 

58-85 

102° 

61-092 

275° 

58-17 

1  1  QO 

Dl  Via 

0/  4Z 

122° 

61063 

350° 

55-94 

132° 

61-047 

400° 

54-34 

142° 

61-080 

450° 

52-70 

152° 

61-011 

500° 

51-02 

162° 

60-092 

600° 

47-64 

TABLE 

SHOWING  THE  BOILING  POINT  FOR  FRESH  WATER  AT  DIFFERENT  ALTI- 
TUDES ABOVE  SEA-LEVEL. 


Boiling  Point 
in  Deg.  Fah. 

Altitude 
above  Sea- 
Level  in  Feet. 

Boiling  Point 
in  Deg.  Fah. 

Altitude 
above  Sea- 
Level  in  Feet 

Boiling  Point 
in  Deg.  Fah. 

Altitude 
above  Sea- 
Level  in  Feet. 

1840 

15,221 

1950 

9,031 

206O 

3,115 

185 

14,649 

196 

8,481 

207 

2,589 

186 

14,075 

197 

7,932 

208 

2,063 

187 

13,498 

198 

7,381 

209 

1,539 

188 

12,934 

199 

6,843 

210 

1,025 

189 

12,367 

200 

6,304 

211 

512 

190 

11,799 

201 

5,764 

212 

Sea-Level  =  0 

191 

11,243 

202 

5,225 

192 

10,685 

203 

4,697 

Below  Sea-Level 

193 

10,127 

204 

4,169 

213 

511 

194 

9,579 

205 

3,642 

THE   ENGINEER  .S  HANDY-BOOK. 


521 


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THE   ENGINEER'S  HANDY-BOOK. 


523 


TABLE 

SHOWING  THE  CAPACITY  OF  CISTERNS  IN  GALLONS  FOR  EACH  10-INCH 

DEPTH. 


Diameter 
IN  Feet. 

Gallons. 

Diameter 
IN  Feet. 

(tALLONS. 

Diameter 
IN  Feet. 

-  - 

a  ATT  riVQ 

2- 



195 

6-6 

206 -8 

12 

705- 

2-5 

30-5 

7- 

239-8 

13 

827-4 

8- 

44-6 

7-5 

275-4 

14 

959-7 

B-5 

59-97 

8- 

313-3 

15 

1101-6 

4- 

78-33 

8-5 

353-7 

20 

1958-4 

4-5 

99-14 

9- 

396-5 

25 

3059-9 

5- 

122-4 

9-5 

461-4 

30 

4406-4 

5-5 

148-1 

lo- 

489-6 

35  • 

5990- 

6- 

176-2 

ll- 

592-4 

40 

7831- 

Rule  for  finding  the  horse-power  of  waterfalls.  —  Multiply  the 
area  of  the  cross-section  of  the  waterfall  in  feet  by  its  velocity  in 
feet  per  minute;  this  product  will  give  the  number  of  cubic  feet 
flowing  through  per  minute.  Multiply  this  by  62^  lbs.,  the  number 
of  pounds  in  a  cubic  foot  of  water.  Multiply  this  last  product  by 
the  fall  in  feet,  and  divide  by  33,000.  The  quotient  will  be  the 
horse-power  of  the  waterfall. 

Example.— With  a  stream  or  flume  10  feet;  depth,  4  feet;  area 
of  cross-section,  40  feet;  velocity  in  feet  per  minute,  150.  Then 
40  X  150  =  6,000  cubic  feet  of  water  per  minute ;  6,000  X  62.1  = 
375,000  pounds  of  water  per  minute.  10  X  375,000  =  3,750,000 
foot-pounds  of  the  waterfall ;  3,750,000  -r-  33,000  =  113y\  horse- 
power of  the  waterfall. 

Rule  for  finding  the  contents  of  an  elliptic  or  oval  tank  in  cubic 
feet  or  gallons, —  Multiply  the  long  diameter  in  inches  by  the 
short  diameter  in  inches,  this  product  by  '7854,  and  this  last  product 
by  the  height  of  the  tank  in  inches ;  then  divide  by  1728,  and  tht 
result  will  be  the  contents  of  the  tank  in  cubic  feet,  which,  if  mul- 
tiplied  by  7*5,  gives  the  number  of  U.  S.  gallons  in  the  tank. 


524 


THE    engineer's  HANDY-BOOK. 


Rule  for  finding  the  quantity  of  water  which  any  square  or  redan- 
gular  box,  or  tank,  is  capable  of  containing  in  cubic  feet  or  U.  S. 
gallons, —  Multiply  the  length  of  the  sides  in  inches  by  their  height 
in  inches ;  then  multiply  the  width  of  the  ends  in  inches  by  their 
height  in  inches.  Add  these  two  products  together  and  divide  by 
1728;  the  product  will  be  the  contents  in  cubic  feet.  This  re- 
sult being  multiplied  by  7*5  gives  the  cubical  contents  in  U.  S. 
gallons. 

Rule  for  finding  the  cubical  contents  of  a  triangular  tank. —  Mul- 
tiply the  length  of  the  base  by  half  its  height ;  multiply  this  by 
.7854,  then  divide  the  product  by  1728 ;  the  quotient  will  be  the 
number  of  cubic  feet,  which,  if  multiplied  by  7*5,  will  give  the 
number  of  U,  S.  gallons  in  the  tank. 

TABLE 


SHOWING  THE  DAILY  AVERAGE  NUMBER  OF  GALLONS  OF  WATER  PER 
INDIVIDUAL  IN  DIFFERENT  CITIES  INCLUDING  THE  QUANTITY  USED 
FOR  MANUFACTURING  PURPOSES,  FOUNTAINS,  ETC. 


158 

Toronto  

.    .  77 

100 

London,  England.  . 

.   .  -29 

50 

Liverpool,     "     .  . 

.   .  23 

55 

Glasgow,  Scotland  . 

.  50 

40 

Edinburgh,   "      '  . 

.  38 

.    .  75 

Dublin,  Ireland  .  . 

.  25 

60 

Paris,  France     .  . 

.  28 

Albany,  N.Y..    .  . 

80 

Tours,       "        .  . 

.  22 

.    ,  83 

Toulouse,  "        .  . 

.  26 

Jersey  City,  N.  J. 

99 

Lyons,      "        .  . 

.  20 

Buffalo,  N.  Y.  .    .  . 

61 

Leghorn,  Italy.    .    .  . 

.  30 

Cleveland  .... 

40 

Berlin,  Prussia    .    .  . 

.  20 

Columbus  .... 

30 

Hamburg,  "       .    .  . 

.  33 

Motitreal  .... 

55 

Richmond,  Va.    .    .  . 

.  36 

San  Francisco     .  . 

.    .  42 

City  of  Mexico    .    .  . 

.  25 

Hartford,  Conn.  .  . 

32 

Vienna  ...... 

.  20 

27 

St.  Petersburg     .    .  . 

.  19 

THE   engineer's  IIANDY-BOOK. 


525 


Vapors, 

The  mechanical  properties  of  vapor  are  similar  to  those  of 
gases  in  general.  When  a  vapor  or  gas  is  contained  in  a  close 
vessel,  the  inner  surface  of  the  vessel  will  sustain  a  pressure  arising 
from  the  elasticity  of  the  fluid.  This  pressure  is  produced  by  the 
mutual  repulsion  of  the  particles,  which  gives  them  a  tendency  to 
fly  asunder,  and  causes  the  mass  of  the  fluid  to  exert  a  force  tend- 
ing to  burst  any  vessel  within  which  it  is  confined.  This  pressure 
is  uniformly  diffused  over  every  part  of  the  surface  of  the  vessel 
in  which  such  fluid  is  contained.  It  is  to  this  quality  that  all  the 
mechanical  power  of  steam  is  due. 

It  is  well  known  from  common  observation,  that  liquids,  if  not 
confined  in  close  vessels,  become  transformed  into  a  condition  re- 
sembling gases  at  ordinary  temperatures,  and  then  disappear. 
This  transformation  takes  place  in  nearly  all  liquids  more  or  less 
rapidly  at  ordinary  temperatures,  though  in  some  it  takes  place 
at  a  very  low  temperature  and  at  an  imperceptible  rate  of  evap- 
oration ;  the  lighter  the  specific  gravity,  the  more  rapidly  it  will 
disappear. 

TABLE 


SHOWING  THE  TEMPERATURE  OF  SATURATED  VAPOR  IN  ATMOSPHERES, 
ACCORDING  TO  ZEUNER. 


Atmospheres. 

Temperature  in 
Degrees  Fah., 
Water. 

Atmospheres. 

Temperattjre  in 
Degrees  Fah., 
Water. 

1 

212° 

6 

318-5° 

2 

248° 

7 

329-5° 

3 

272° 

8 

339-0° 

4 

291° 

9 

3480° 

5 

306° 

10 

857-0° 

J 

526 


THE   ENGINEER'S  HANDY-BOOK. 


TABLE 


SHOWING  THE  PRESSURE  AND  TEMPERATURE  OF  THE  VAPORS  OF  WATER 
FROM  32°  TO  400°  FAH. 


Temp. 
Fah. 

Pressures 
in  Atmos- 

Pressures 
in  Lbs.  per 
S(][.  Incli. 

Differ- 
ences. 

Temp. 
Fah. 

Pressures 
in  Atmos- 

Pressures 
in  Lbs.  per 
Sq.  Inch. 

Differ- 
ences. 

32 

0-006 

0-09 

0-00 

73 

0-026 

0-38 

0-02 

33 

0-006 

0-09 

0-00 

74 

0-027 

0-40 

0-01 

34 

0-006 

0-09 

0-01 

75 

0-028 

0-41 

0-02 

35 

0-007 

0-10 

0-00 

76 

0-029 

0-43 

003 

36 

0-007 

0-10 

0-01 

77 

0-031 

0-46 

0-00 

37 

0-007 

0-11 

O'Ol 

78 

0-031 

0-46 

0-01 

38 

0-008 

0-12 

0-00 

79 

0-032 

0-47 

0-00 

39 

0-008 

0-12 

0-01 

80 

0-032 

0-47 

0-02 

40 

0-009 

0-13 

0-00 

81 

0-033 

0-49 

0-01 

41 

0-009 

0-13 

0-01 

82 

0034 

0-50 

0-03 

42 

0-009 

0-14 

0-00 

83 

0-036 

0-53 

0-01 

43 

0-009 

0-14 

0-01 

84 

0-037 

0-54 

0-oa 

44 

0-010 

0-15 

0-00 

85 

0-039 

0-57 

0-03 

45 

0-010 

0-15 

0-01 

86 

0-041 

0-60 

0-02 

46 

0-011 

0-16 

0-00 

87 

0-042 

0-62 

0-01 

47 

0-011 

0-16 

0-01 

88 

0-043 

0-63 

0-02 

48 

0-011 

0-17 

0-00 

89 

0-044 

0-65 

0-03 

49 

0-011 

0-17 

0-01 

90 

0-046 

0-68 

0-03 

50 

0-012 

0-18 

0-00 

91 

0-048 

0-71 

0-01 

51 

0-012 

0-18 

0-01 

92 

0-049 

0-72 

0-02 

52 

0-013 

0-19 

0-01 

93 

0-050 

0-74 

0-02 

53 

0-013 

0-20 

0-01 

94 

0-052 

0-76 

0-05 

54 

0-014 

0-21 

0-00 

95 

0-055 

0-81 

0-03 

55 

0-014 

0-21 

0-01 

96 

0-057 

0-84 

0-01 

56 

0-015 

0-22 

0-02 

97 

0-058 

0-85 

0-05 

57 

0-016 

0-24 

0-00 

98 

0-061 

0-90 

0-00 

58 

0-016 

0-24 

0-01 

99 

0-061 

0-90 

0-03 

59 

0-017 

0-25 

001 

100 

0-063 

0-93 

004 

60 

0-018 

0-26 

0-00 

101 

0-066 

0-97 

0-01 

61 

0-018 

0-26 

0-00 

102 

0-067 

0-98 

0-03 

62 

0-018 

0-26 

0-02 

103 

0-069 

1-01 

0-05 

63 

0-019 

0-28 

0-01 

104 

0-072 

1-06 

0-03 

64 

0-020 

0-29 

0-00 

105 

0-074 

1-09 

0-06 

65 

0*020 

0-29 

0-02 

106 

0-078 

1-15 

0-01 

66 

0-021 

0-31 

0-01 

107 

.  0-079 

1-16 

0-02 

67 

0-022 

0-32 

0-02 

108 

0-080 

1-18 

0-04 

68 

0-023 

0-34 

0-00 

119 

0-083 

1-22 

0-04 

69 

0-023 

0-34 

0-01 

110 

0-086 

1-26 

0-03 

70 

0-024 

0-35 

0-00 

111 

0-088 

1-29 

0-05 

71 

0-024 

0-35 

0-02 

112 

0-091 

1-34 

0-03 

72 

0-025 

0-37 

0-01 

113 

0-093 

1-37 

0-03 

THE    KNGINEEU\S  flANDY-BOOK. 


TABLE  —  {Continued.) 


Temp. 
Fah. 

Pressures 
in  Atmos- 
pheres. 

Pressures 

111  LjUS,  JJCl 

Sq.  Inch. 

Differ- 
ences. 

Temp. 
Fah. 

Pressures 
in  Atmos- 
pheres. 

X  I  ens  111  Co 

in  Lbs.  per 
iSq.  Inch. 

Differ- 
ences. 

114 

0-095 

1-40 

0*07 

157 

0-300 

4  41 

u  uy 

115 

0-100 

1-47 

0-03 

158 

0*306 

4  OU 

U  Uo 

116 

0-102 

1*50 

0*04 

159 

0*308 

A  •ceo 

4  00 

U  14 

117 

0-105 

1-54 

003 

160 

0*318 

A'fi.1 
4  D/ 

U  11 

118 

0-107 

1-57 

0*08 

161 

4  /o 

u  ly 

119 

0-112 

1-65 

003 

162 

(T-338 

4  y/ 

U  Iv 

120, 

0-114 

1-68 

004 

163 

0*345 

0  u/ 

121 

0-117 

1*72 

0-06 

164 

0*353 

K.I  0 

u  iz 

122 

0-121 

1-78 

004 

165 

0*361 

0  oi 

K)  14 

123 

0-124 

1-82 

0-05 

166 

0*371 

0  40 

u  iz 

124 

0-127 

1-87 

0*04 

167 

03/9 

0  01 

yj  \jL 

125 

0-130 

1-91 

0-09 

168 

0*387 

0  by 

A*!  0 
U  lo 

126 

0-136 

2-00  . 

0*04 

169 

0*396 

0  oZ 

U  16 

127 

0-139 

2-04 

0-05 

170 

0*405 

0  yo 

Kj  10 

128 

0-142 

2-09 

006 

171 

0*415 

D  lU 

U  10 

129 

0-146 

2-15 

0-05 

172 

0*425 

D  ZO 

A.I  A 

U  10 

130 

0-150 

2-20 

0-06 

173 

0*436 

0  41 

A»1  Q 

U  lo 

131 

0-154 

2-26 

0-06 

174 

0*445 

D  04 

A'l  Pi 

U  10 

132 

0-158 

2-32 

0-06 

175 

0*455 

6*69 

A.I  A 

U  lo 

133 

0-162 

2-38 

0-06 

176 

0*466 

D  OO 

U  10 

134 

0-166 

2-44 

0-09 

177 

0*476 

7  UU 

A'l 

U  10 

135 

0-172 

2-53 

0-04 

178 

0*488 

T.I  ^ 

A. 91 
U  Zl 

136 

0-175 

2-57 

0-09 

179 

0*501 

7  00 

A.I  Q 

U  lc> 

137 

0-181 

2-66 

0-03 

180 

0*513 

7  04 

A'l  9 
U  IZ 

138 

0-183 

2-69 

0*12 

181 

0*521 

7  DO 

A.I  ^ 
U  10 

139 

0-191 

2-81 

0-07 

182 

0*531 

7  ol 

A.I  7 
U  1/ 

140 

0-196 

2-88 

0-06 

183 

0*543 

7  yo 

A'l  Q 

u  ly 

141 

0-200 

2-94 

0-07 

184 

0*556 

0.1  7 

0  1/ 

A'l  Q 

u  ly 

142 

0-205 

3-01 

008 

185 

0*569 

o.o^i 
0  oO 

A.I  Q 
U  lo 

143 

0-210 

3-09 

0*10 

186 

0-581 

0  04 

A'l  Q 

U  lo 

144 

0-217 

3-19 

0-04 

187 

0*593 

O.'TO 

o7Z 

A.I  7 
U  1  / 

145 

0-220 

3-23 

0-09 

188 

0*605 

0  by 

A'l  Q 

u  ly 

146 

0-226 

3-32 

0-08 

189 

0*618 

9*08 

A. 91 

u  Zl 

147 

0-231 

3-40 

0-10 

190 

0631 

9*29 

A. 91 

U  Zl 

148 

0-238 

3-50 

0*10 

191 

0*646 

9*50 

A.99 

u  zz 

149 

0-245 

3-60 

0-09 

192 

0*661 

V  iZ 

A*  99 

150 

0-251 

3-69 

0-02 

193 

0*676 

9*94 

A.99 

u  zz 

151 

0-259 

3-81 

0-09 

194 

0*691 

10*16 

0*20 

152 

0-265 

3-90 

U  Oo 

lyo 

A.7rvr: 
U  /UO 

0*21 

153 

0-271 

3-98 

0-11 

196 

0*719 

10*57 

0*22 

154 

0-278 

4-09 

0-10 

197 

0*734 

10*79 

0*22 

155 

0-285 

4-19 

0-06 

198 

0*749 

11*01 

0*22 

156 

0-289 

4-25 

0-16 

199 

0*764 

11*23 

0*22 

528  THE  engineer's  handy-book. 


TABLE  —  ( Continued.) 


r 

Temp. 
Fah. 

X  ressu  res 
in  Atmos- 
pheres. 

X ressures 
in  Lbs.  per 
Sq.  Inch. 

Differ- 
ences. 

Temp. 
Fah. 

X  ressures 
in  Atmos- 
pheres. 

"ressu  res 
in  Lbs.  per 
Sq.  Inch. 

Differ- 
ences. 

200 

U  77U 

I  1  .  /I  c 

II  45 

A.I  O 

243 

1*794 

26*37 

A.  /IT 

0  47 

201 

U  7o7 

11*57 

A. OK 

244 

1*826 

26*84 

A. /I  A 

0  49 

202 

A. OA/1 

11*82 

A. /I  O 

U  4o 

245 

1*859 

27*33 

A.CA 

0  50 

203 

0'833 

12*25 

0*25 

246 

1*893 

27*83 

0*51 

204 

A.O  KA 

12*50 

U  Z4 

247 

1*928 

28*34 

A.KA 

0  oO 

205 

0'867 

12*7^ 

0*27 

248 

1*962 

28*84 

0*52 

206 

13*01 

A.OO 

249 

1*997 

A.K1 
0  Ol 

207 

A.AA/I 

13*29 

A.OO 

250 

2*032 

29*87 

A.  KO 

0  Oo 

208 

0*923 

13*57 

0*28 

251 

2*068 

30*40 

0*53 

209 

0*942 

13*85 

0*28 

252 

2*104 

30*93 

0*54 

210 

0*961 

14*13 

0*29 

253 

.  2*141 

31*47 

0*56 

211 

0*981 

14*42 

0*28 

254 

2*179 

3203 

0*57 

212 

1*000 

14*77 

0*30 

255 

2*217 

32*60 

0*56 

213 

1*020 

15*00 

0*29 

256 

2*256 

33*16 

0*56 

214 

1*040 

15*29 

A.01 

U  ol 

257 

2*294 

OO.TO 

A.KA 

0*59 

215 

1*061 

15*60 

0*32 

258 

2*334 

34*31 

0*59 

216 

1*083 

15*92 

A.O  1 

0*31 

259 

2*374 

34*90 

0*60 

217 

1  .1  A/1 

1  104 

16*23 

A.01 

U  ol 

0£?A 

2o0 

2*415 

6b  o\J 

A.^A 

0  oU 

218 

1*125 

1        C  /I 

1d*54 

A.OO 

261 

2*456 

O^J.I  A 

0  oZ 

219 

1*147 

16*86 

A.OO 

0£f  o 

2*498 

OD  7^ 

U  DO 

220 

1*169 

17*18 

A.OO 

263 

o.r:  /1 1 
Z  541 

o7  oO 

A.^O 
0  DO 

221 

1*191 

17*51 

0*35 

264 

2*584 

37*98 

0*64 

222 

1*215 

17*86 

0*34 

265 

2*627 

38*62 

A./?  A 

0  64 

223 

1*238 

18*20 

0*34 

266 

2*671 

39*26 

0*67 

224 

1*261 

18*54 

A.O  C 
0  OO 

267 

2*716 

OA. AO 

oy  yo 

U  DD 

225 

1*285 

18*89 

0*35 

268 

2*761 

40*59 

A/3T 

0  d7 

226 

1*309 

19*24 

A. 0*7 

269 

2*807 

A  t  .O/J 

41*ZD 

0  oy 

227 

1*334 

19*61 

c\.on 

y)  61 

270 

2*854 

/1 1  .AK 

4i*yo 

0  by 

228 

1*359 

19*98 

A.OO 

0*00 

271 

O.AA1 

2*901 

A.T1 

U  71 

229 

1*385 

20*36 

0*44 

272 

2*949 

/lO.OC 

43  35 

A.T1 

0  71 

230 

1*415 

20*80 

A.  /I  A 

U  40 

273 

2*997 

A  A.na 
44  Oo 

A. TO 

0  7Z 

231 

1*442 

21*20 

0*39 

274 

3*046 

44*78 

A.TK 

0*7o 

232 

1*469 

21*59 

0*42 

275 

3*097 

/I  x.co 

4o  5o 

A. TO 
0  /  O 

233 

1*497 

22*01 

0*41 

276 

3*147 

4d  2o 

A.T  K 

0  7o 

234 

1*525 

22*42 

0*41 

277 

3*198 

/IT.Al 

47  01 

A.TT 

0  77 

235 

1*553 

22*83 

0*43 

278 

3*250 

/IT  .TO 

47  7o 

A.TT 

0  77 

236 

1*582 

23*26 

0*44 

279 

3*303 

48  00 

A. OA 

0  oU 

237 

1*612 

23*70 

0*42 

280 

3*357 

49*35 

0*79 

9S1 

V  O-L 

239 

1*670 

24*55 

0*44 

282 

3*466 

50*95 

0*81 

240 

1*700 

24*99 

0*45 

283 

3*521 

51-76 

0*81 

241 

1*731 

25*45 

0*45 

284 

3*576 

52*57 

0*82 

242 

1*762 

25-90 

0*47 

285 

3*632 

53*39 

0*84 

THE    KNGINEER^S    HANDY-BOOK.  529 


TABLE  —  (Continued.) 


Temp. 
Fall. 

Pressures 
in  Atmos- 
pheres. 

Pressures 
in  Lbs.  per 
Sq. Inch. 

Diner- 
ences. . 

1  emp. 
Fah. 

Pressures 
in  Atmos- 
pheres. 

Pressures 
in  Lbs.  per 
Sq.  Inch. 

i-'iner- 
ences. 

286 

3-689 

54-23 

0-85 

329 

6*945 

102*09 

1*44 

287 

3*747 

55-08 

0-87 

330 

7*043 

103-53 

1*44 

288 

3-806 

55-95 

0*88 

331 

7*141 

104-97 

1*44 

289 

3-866 

56-83 

0*88 

332 

7*239 

106-41 

1-46 

290 

3-926 

57-71 

0-90 

333 

7*338 

107-87 

1-45 

291 

3-987 

58-61 

0-91 

334 

7*437 

109-32 

1-46 

292 

4-049 

59-52 

0-93 

335 

7*536 

110-78 

1*50 

293 

4-112 

60-45 

0-92 

336 

7*638 

112-28 

1-51 

294 

4-175 

61-37 

0-94 

337 

7-741 

113-79 

1-55 

295 

4-239 

62-31 

0-96 

338 

7-846 

115-34 

1-55 

296 

4-304 

63-27 

0-97 

'339 

7-952 

116-89 

1*59 

297 

4-370 

64-24 

0-98 

340 

8-060 

118*48 

1-60 

298 

4-437 

65-22 

100 

341 

8-169 

120-08 

1-62 

299 

4-505 

66-22 

1-02 

342 

8-279 

121-70 

1-62 

300 

4-574 

67-24 

1*01 

343 

8-389 

123-32 

1*63 

301 

4-643 

68-25 

1*02 

344 

8-500 

124-95 

1-65 

302 

4-712 

69-27 

1-03 

345 

8-612 

126-60 

1*64 

303 

4-782 

70-30 

1-04 

346 

8-724 

128-24 

1*68 

304 

4-853 

71-34 

1-06 

347 

8-838 

129-92 

1-69 

305 

4-925 

72-40 

107 

348 

8*953 

131-61 

1*72 

306 

4-998 

73-47 

1-09 

349 

9-070 

133-33 

1-75 

307 

5-072 

74-56 

1*10 

350 

9-189 

135*08 

1-78 

308 

5-147 

75-66 

1-12 

351 

9-310 

136-86 

1-81 

309 

5-223 

76-78 

1-13 

352 

9*433 

138-67 

1*80 

310 

5-300 

77-91 

1-16 

353 

9*556 

140*47 

1*83 

311 

5-379 

79-07 

1-16 

354 

9*680 

142*30 

1*82 

312 

5-458 

80-23 

1-18 

355 

9-804 

144-12 

1-84 

313 

5-538 

81-41 

1*19 

356 

9-929 

145-96 

1-85 

314 

5-619 

82-60 

1-20 

357 

10*055 

147-81 

1-87 

315 

5-701 

83-80 

1-22 

358 

10-182 

149-68 

1-89 

316 

5-784 

85-02 

1-22 

359 

10*311 

151*57 

1-93 

317 

5-867 

86-24 

1-24 

360 

10*442 

153-50 

1*95 

318 

5*951 

87*48 

1*23 

361 

10*575 

155*45 

1'99 

319 

6-035 

88-71 

1*27 

362 

10-710 

157-44 

2-01 

320 

6*121 

89-98 

1*28 

363 

10*847 

159-45 

2-03 

321 

6-208 

91-26 

1*29 

364 

10-985 

161-48 

203 

322 

6-296 

92-55 

1*31 

S65 

11*123 

163-51 

2*04 

323 

6-385 

93-86 

1-32 

366 

11*262 

165-55 

2-04 

324 

6-475 

95-18 

1-34 

367 

11-401 

167-59 

2-08 

325 

6-556 

96-42 

1-35 

368 

11-542 

169-67 

2*08 

326 

6-658 

97-87 

1-37 

369 

11-684 

171-75 

2-14 

327 

6-751 

99*24 

1*40 

370 

11-829 

173-89 

2-16 

328 

6*846 

100-64 

1*45 

371 

11-976 

176-05 

2-19  1 
1 

45  21 


530         THE  engineer's  handy-book. 


TABLE  —  {Continued.) 


Temp. 
Fah. 

Jr  ressures 
in  Atmos- 
pheres. 

1  ressures 
in  Lbs.  per 
Sq.  Inch. 

Differ- 
ences. 

Temp. 
Fah. 

X  ressures 
in  Atmos- 
pheres. 

X  ressures 
in  Lbs.  per 
Sq. Inch. 

Differ- 
ences. 

372 

1  O.I  OK 

lA'Vlo 

17o  24 

O.I  A 

2  19 

OCT 
OO/  . 

14  OlU 

01  O.OA 

21o  oU 

2-51 

Si  6 

12  274 

loU  4o 

o>oo 
2  22 

OQO 
OOO 

14  Dol 

oi  K.OI 

210  ol 

2-54 

1  o.  /I  oc; 
12  420 

lo2  DO 

o«oo 
2  22 

OQA 

ooy 

1 4  o04 

oi  Q.oc; 
21o  OO 

2*58 

o/o 

12  o7d 

lo4  o/ 

O.OO 

2  2o 

OOA 

10  U2y 

OOA.AO 

22U  yo 

2-60 

Old 

12  72o 

lo7  lU 

2  2o 

oyi 

lo  2Uo 

OOO-KO 

22o  Oo 

2-56 

611 

12  ool 

ioy  oO  • 

2  2d 

QOO 

oy2 

10  ooU 

OO/^.AA 

22d  oy 

2*13 

o7o 

lo  Ut5o 

1"J1  oi». 

O.OQ 

2  2o 

oyo 

10  40/ 

OOT.OO 

22/  22 

2*d4 

379 

13'190 

193-86 

O.O  1 

2  ol 

oy4 

lo  DO/ 

229-86 

2*69 

380 

13'347 

lyo  20 

2  OO 

oyo 

lo  o2U 

000.  p:  c; 

2o2  00 

2*65 

381 

13-507 

198-55 

2-40 

396 

16-000 

235-20 

2-Z9 

382 

13-f)70 

200-95 

2-44 

397 

16*190 

237-99 

2-37 

383 

13-836 

203-39 

2-45 

398 

16-385 

240-86 

2-90 

384 

14-003 

205-84 

2-47 

399 

16-582 

243-76 

2-94 

385 

14-171 

208-31 

2-49 

400 

16-782 

246-70 

3-04 

386 

14-340 

210-80 

2-50 

Gases. 

All  substances,  whether  animal,  vegetable,  or  mineral,  consisting 
of  carbon,  hydrogen,  and  oxygen,  when  exposed  to  a  red  heat,  i 
produce  various  inflammable  elastic  fluids  capable  of  furnishing  | 
artificial  light.    The  products  of  perfect  combustion  are  gases  j 
which  form  in  accordance  with  unchangeable  laws.    Many  of  the  j 
gases  have  already  been  brought  into  the  liquid  state  by  the  con-  \ 
joint  agency  of  cold  and  compression,  and  all  of  them  are  proba- 
bly susceptible  of  a  similar  reduction  by  the  use  of  means  suflS- 
ciently  powerful  for  the  required  end.    They  must  consequently 
be  regarded  as  the  superheated  steams  or  vapors  of  the  liquids 
into  which  they  are  compressed. 

When  a  gas  or  vapor  is  compressed  into  half  its  original  bulk, 
its  pressure  is  double ;  when  compressed  into  a  third  of  its  original 
bulk,  its  pressure  is  trebled ;  w^hen  compressed  into  a  fourth  of  its 
original  bulk,  its  pressure  is  quadrupled ;  and  generally  the  press- 
ure varies  inversely  as  the  bulk  into  which  the  gas  is  compressed. 
So  in  like  manner,  if  the  volume  be  doubled,  the  pressure  is  made 


THE   ENGINEEr\s  HANDY-ROOK. 


531 


one-half  of  what  it  was  before, —  the  pressure  in  every  case  being 
reckoned  from  0,  or  from  a  perfect  vacuum. 

Thus,  if  we  take  the  average  pressure  of  the  atmosphere  at  14*7 
pounds  on  the  square  inch,  a  cubic  foot  of  air,  if  suffered  to  expand 
into  twice  its  bulk,  by  being  placed  in  a  vacuum  measuring  two 
cubic  feet,  will  have  a  pressure  of  7*35  pounds  above  a  perfect 
vacuum,  and  also  of  7*35  pounds  below  the  atmospheric  press- 
ure ;  whereas,  if  the  cubic  foot  be  compressed  into  a  space  of 
half  a  cubic  foot,  the  pressure  will  become  29*4  pounds  above 
a  perfect  vacuum,  and  14*7  above  the  atmospheric  pressure. 
The  specific  gravity  of  any  one  gas  to  that  of  another  will  not 
exactly  conform  to  the  same  ratio  under  different  degrees  of  heat, 
and  other  pressures  of  the  atmosphere. 

Oxygen  is  the  name  given  to  the- solid  particles  of  oxygen  gas, 
which  is  a  combination  of  oxygen,  caloric,  and  light,  and  is  the 
simplest  form  in  which  oxygen  can  be  obtained.  Oxygen  is  called 
the  radical  or  base  of  the  gas ;  and  the  same  mode  of  expression 
is  used  in  other  cases.  Oxygen  enters  into  chemical  combination 
with  a  great  number  of  substances,  in  which  it  exists  in  a  concrete 
or  solid  state ;  it  is  by  the  application  of  heat,  or  of  acids,  to  some 
of  the  substances  containing  it,  that  it  is  usually  procured  in  the 
form  of  gas.  Oxygen  gas  is  the  only  one  that  can  be  breathed  by 
animals  for  any  length  of  time  with  impunity.  The  power  of  at- 
mospheric air  in  supporting  respiration  is  owing  to  the  oxygen. 
Oxygen  combines  with  all  the  metals,  and  in  this  state  they  are 
called  metallic  oxides,  depriving  them  of  their  metallic  lustre,  and 
giving  them  an  earthy  or  rusty  appearance.  Any  of  the  metals 
are  capable  of  combining  with  different  proportions  of  oxygen. 
Those  with  one  proportion  are  called  protoxides;  of  two,  deiif oxides ; 
those  of  three,  tritoxides. 

Nitrogen. — Nitrogen  gas  is  most  easily  described  by  including 
many  of  its  negative  qualities.  It  has  no  taste;  it  unites  with 
oxygen  in  several  proportions ;  it  also  unites  with  hydrogen. 
Though  incapable  of  being  breathed  above  its  base,  nitrogen  is  a 
component  portion  of  all  animal  substances ;  it  is  lighter  than  oxy- 


532  THE   ENGINEER'S  HANDY-BOOK. 

gen.  Nitrogen  gas  may  be  variously  obtained.  If  the  oxygen  be 
extracted  from  the  atmospheric  air,  this  substance  will  remain,  and 
will  generally  be  very  pure,  unless  the  oxygen  has  been  extracted 
by  respiration.  If  iron  filings  and  sulphur,  moistened  with  water, 
be  put  into  a  jar  containing  atmospheric  air,  this  gas  will  in  a  day 
or  two  be  all  the  air  that  remains  in  the  jar,  as  the  oxygen  will 
be  absorbed  by  the  iron  and  sulphur.  Phosphorus  or  sulphuret 
of  lime  or  potass,  inclosed  with  common  air  in  a  jar,  will  produce 
a  similar  effect. 

Hydrogen.— Hydrogen,  like  oxygen  and  nitrogen,  is  invisible, 
elastic,  and  inodorous ;  but  the  last  quality  it  seldom  possesses,  be- 
cause  it  is  very  seldom  perfectly  dry,  and  when  it  contains  water 
in  solution,  like  alkaline  sulphurets,  its  odor  is  considerably  fetid. 
Hydrogen  with  oxygen  forms  water;  and  it  is  by  the  decomposi- 
tion of  water  that  chemists  obtain  it  in  the  greatest  abundance 
and  purity.  For  this  purpose  iron  filing  or  turnings,  or  granu-^ 
lated  zinc,  are  put  into  a  retort,  and  covered  with  sulphuric  acid 
diluted  with  four  times  its  weight  in  water.  A  violent  effervescence 
ensues,  a  large  quantity  of  gas  is  evolved,  and  issuing  from,  the 
retort  is  collected  in  the  usual  manner  by  the  pneumatic  appa- 
ratus. In  this  experiment  the  acid  is  not  decomposed;  it  is  the 
oxygen  of  the  water  with  which  the  acid  is  diluted  that  seizes  upon'; 
and  oxidizes  the  metal,  and  the  hydrogen,  in  the  same  portion  of  ' 
water  being  thus  disengaged,  passes  over  in  the  state  of  gas.  The 
hydrogen  obtained  by  using  zinc  is  the  purest,  that  obtained  by 
using  iron  generally  containing  some  carbon. 

Hydrogen  combines  with  a  larger  quantity  of  oxygen  than  any 
other  body ;  its  combustion,  therefore,  when  mixed  with  oxygen, 
produces  a  more  intense  heat  than  any  other  combustion. 

Carbon.  — Vegetables,  when  burnt  or  distilled  in  close  vessels 
till  their  volatile  parts  are  entirely  separated,  leave  a  black,  brittle 
and  cinereous  substance  which  constitutes  the  greater  part  of  the 
woody  fibre,  and  is  called  charcoal  Charcoal  contains  a  portion 
of  earthy  and  saline  impurities,  but,  when  entirely  freed  from  these 
and  other  impurities,  a  solid,  simple,  combustible  substance  re- 


THE   ENGINEEr\s  HANDY-BOOK. 


533 


mains,  which  is  called  carbon.  Carbon  exists  naturally  in  a  state 
of  greater  purity  than  can  be  prepared  by  art.  The  diamond  is 
pure  carbon  crystallized,  and  when  pure  is  colorless  and  transpa- 
rent. It  is  the  hardest  substance  known ;  and,  as  it  sustains  a 
considerable  degree  of  heat  unchanged,  it  was  formerly  considered 
to  be  incombustible.  It  may,  however,  be  consumed  by  a  burning- 
glass,  and  even  by  the  heat  of  a  furnace.  The  difficulty  of  burning 
it  appears  to  arise  from  its  hardness ;  for  Morveau  and  Tennaut 
have  rendered  common  charcoal  so  hard,  by  exposing  it  for  some 
time  to  a  violent  fire  in  close  vessels,  that  it  endured  a  red  heat 
without  catching  fire.  Common  charcoal  contains  only  64  parts 
of  diamond,  or  pure  carbon,  and  36  of  oxygen  in  every  100. 

The  common  charcoal  of  commerce  is  usually  prepared  from 
young  wood,  which  is  piled  up  near  the  place  where  it  is  cut  in 
conical  heaps,  covered  with  earth,  and  burnt  with  the  least  pos- 
sible access  of  air.  When  the  fire  is  supposed  to  have  penetrated 
to  the  centre  of  the  thickest  pieces,  it  is  extinguished  by  entirely 
closing  the  vents.  When  charcoal  is  wanted  very  pure,  the  pro- 
duct of  this  mode  of  preparing  it  will  not  suffice ;  for  the  manu- 
facturing of  the  best  gunpowder,  it  is  distilled  in  iron  cylinders. 
Chemists  prepare  it  in  small  quantities  in  a  crucible  covered  with 
sand,  and  after  they  have  thus  prepared  it,  they  pound  it,  and 
wash  away  the  salts  it  contains  by  muriatic  acid  ;  the  acid  is  re- 
moved by  the  plentiful  use  of  water,  and  afterwards  the  charcoal 
is  exposed  to  a  low  red  heat.  Pure  charcoal  is  perfectly  tasteless 
and  insoluble  in  water. 

Charcoal  newly  prepared  absorbs  moisture  with  avidity.  It 
also  absorbs  oxygen  and  other  gases,  which  are  condensed  in  its 
pores  in  quantity  many  times  exceeding  its  ow^n  bulk,  and  which 
are  given  out  unaltered.  Fresh  charcoal  allowed  to  cool  without 
exposure  to  air,  and  the  gas  then  admitted,  will  absorb  2*25  times 
its  bulk  of  atmospheric  air  immediately,  and  75  per  cent,  more 
in  four  or  five  hours ;  of  oxygen  gas  about  1*8  immediately,  aod 
slowly  one  more;  of  nitrogen  gas,  1*65  immediately. 
45* 


534 


THE   engineer's  HANDY-BOOK. 


Technical  and  Chemical  Terms  as  Applied  to  Substances 
that  bear  Relations  to  the  Steam -Engine  both  in  Theory 
and  Practice. 

Alkali,  or  antacid,  means  any  substance  which,  when  mingled 
with  acid,  produces  fermentation. 

Ammonia.  — This  alkali,  when  perfectly  caustic,  enables  chem- 
ists to  distinguish  between  the  salts  of  lime  and  those  of  magnesia, 
as  it  precipitates  the  earth  from  the  latter  salts,  but  not  from  the 
former. 

Analysis  means  resolution,  by  chemistry,  of  any  matter  into  its 
primary  and  constituent  parts. 

Atoms. — In  the  chemical  combination  of  bodies  with  each 
other,  it  is  observed  that  some  unite  in  all  proper  proportions ; 
others  in  all  proportions  as  far  as  a  certain  point  beyond  which 
combination  no  longer  takes  place.  There  are  also  many  examples 
in  which  they  unite  in  one  proportion  only,  and  others  in  several 
proportions ;  and  these  proportions  are  definite,  and  in  the  inter- 
mediate ones  no  combination  ensues. 

Bases.  — This  term  is  usually  applied  to  alkalies,  earths,  and 
metallic  oxides  in  their  relations  to  the  acids  and  salts.  It  is 
sometimes  also  applied  to  the  particular  constituents  of  an  acid 
or  oxide,  on  the  supposition  that  the  substance  combined  with  the 
oxygen,  etc.,  is  the  basis  of  the  compound  to  which  it  owes  its 
particular  qualities. 

Calcination. — This  term  is  applied  to  the  fixed  residues  of 
such  matters  as  have  undergone  combustion,  and  are  called  cin- 
ders in  common  language,  and  oxides  by  chemists.    This  opera- 
tion, when  considered  with  regard  to  these  residues,  is  termed- 
calcination. 

Combination  is  understood  to  be  the  intimate  union  of  the  pai- 


THE    engineer's  HANDY-BOOK. 


535 


tides  of  different  substances  by  chemical  attraction,  so  as  to  form 
a  compound  possessed  of  new  and  peculiar  properties. 

Compound.  —  A  compound  is  the  result  or  effect  of  a  compo- 
sition of  different  things,  or  that  which  arises  from  them.  It 
stands  opposed  to  simple. 

Equivalents  are  terms  introduced  into  chemistry  to  express  the 
system  of  definite  ratios  in  which  the  molecular  atoms  of  this  sci- 
ence reciprocally  unite. 

Evaporation  is  a  chemical  process  usually  performed  by  apply- 
ing heat  to  any  compound  substance,  in  order  to  dispel  the  vola- 
tile parts. 

Fixed. — This  epithet  is  applied  to  such  bodies  as  so  far  resist 
the  action  of  heat  so  as  not  to  rise  in  vapor.  It  is  the  opposite 
of  volatile;  but  it  must  be  observed  that  the  fixity  of  bodies  is 
merely  a  relative  term,  as  an  adequate  degree  of  heat  will  dissi- 
pate all. 

Neutral. — A  term  applied  to  saline  compounds  of  an  acid  or 
alkali  nature,  which  are  so  called,  because  they  do  not  possess  the 
characters  of  acid  or  alkaline  salts. 

Neutralization. — This  term  is  applied  when  acid  and  alkaline 
matter  are  combined  in  such  proportion  that  the  compound  does 
not  change  the  color  of  litmus  or  violets,  in  which  condition  they 
are  said  to  be  neutralized. 

Oxide.  —  Any  substance  which  combines  with  oxygen  without 
being  in  the  state  of  an  acid  is  an  oxide. 

Oxidation.  — This  term  is  applied  to  the  process  of  converting 
metals  and  other  substances  into  oxides  by  combining  with  them  a 
certain  portion  of  oxygen. 

Phosphate  is  a  salt  formed  by  the  union  of  phosphoric  acid 


536 


THE   ENGINEEK^S  HANBY-BOOK. 


with  salifiable  bases ;  thus,  phosphate  of  ammonia,  phosphate  of 
lime,  etc. 

Pyrites.  —  Substances  which  strike  fire  when  rubbed  or  thrown 
together.  They  are  frequently  found  in  bituminous  coal,  and  often 
induce  spontaneous  combustion. 

Saline. —A  term  applied  to  any  substance  of  a  salty  nature. 
The  number  of  saline  substances  is  very  considerable,  and  they 
possess  peculiar  characters  by  which  they  are  distinguished  from 
other  substances. 

Saturation.  —  A  term  applied  to  bodies  which  have  a  chemical 
afiinity  for  each  other,  and  which  will  only  unite  in  certain  pro- 
portions. When,  therefore,  a  fluid  has  dissolved  as  much  of  any 
substance  as  it  is  capable  of  dissolving,  it  is  said  to  have  reached 
the  point  of  saturation.  Thus,  water  will  dissolve  one-quarter  of 
its  weight  of  common  salt,  and  if  more  salt  be  added,  it  will  sink 
to  the  bottom  in  a  solid  state. 

Areas  of  Circles. 

The  term  area  means  any  opening  or  flat  surface  confined  be- 
tween any  lines;  a  definite  space;  superficial  contents  of  any  fig- 
ure  ;  any  plain  space  or  surface  included  within  any  given  lines ; 
but  when  used  in  connection  with  the  steam-engine,  it  means  the 
number  of  square  inches  in  the  piston,  or  valve,  against  which  the 
steam  acts,  as  the  case  may  be. 

A  circle  may  be  considered  as  composed  of  many  triangles, 
whose  bases  are  the  circumference  of  the  circle,  and  whose  vertices 
are  coincident  with  the  centre  of  the  circle.  If  a  cylinder  be 
drawn,  whose  height  equals  i  its  diameter,  the  convex  surface  of 
such  a  cylinder  is  just  equal  to  the  area  of  the  circle.  A  circular 
vessel  will  contain  a  greater  quantity  than  a  vessel  of  any  other 
shape  made  of  the  same  amount  of  material.  The  areas  of  cir- 
cles are  to  each  other  as  the  square  of  their  diameters.  The  di- 
ameter  of  a  circle  being  1,  its  circumference  equals  3-1416. 


THE   engineer's  HANDY-BOOK. 

The  diameter  of  a  circle  is  a  straight  line  drawn 
through  its  centre,  touching  both  sides,  thus  

The  radius  of  a  circle  is  half  the  diameter  

A  chord  is  a  straight  line  joining  any  two  places  in 
the  circumference  of  a  circle  

The  versed  sine  is  a  perpendicular  joining  the  middle 
of  the  chord  and  circumference  of  a  circle...  

An  arc  is  any  part  of  the  circumference  of  a  circle... 
A  triangle  has  3  sides  and  3  angles  

A  parallelogram  has  4  sides  and  4  angles  

A  pentagon  has  5  sides  and  5  angles  

A  hexagon  has  6  sides  and  6  angles  

A  heptagon  has  7  sides  and  7  angles  

An  octagon  has  8  sides  and  8  angles  


538  THE   ENGINEER'S  HANDY-BOOK. 


A  nonagon  has  9  sides  and  9  angles 


A  decagon  has  10  sides  and  10  angles. 


An  endeeagon  has  11  sides  and  11  angles 


A  dodecagon  has  12  sides  and  12  angles. 


Eules. 

To  find  the  circumference  of  a  circle,  multiply  the  diameter  by 
3  1416 ;  the  product  is  the  circumference. 

To  find  the  diameter  of  a  circle,  divide  the  circumference  by 
3-1416,  the  quotient  is  the  diameter  ;  or  multiply  the  square  root 
of  the  area  by  1*12837,  the  product  is  the  diameter. 

To  find  the  area  of  a  circle,  multiply  the  square  of  the  diam- 
eter by  '7854,  the  product  is  the  area ;  or  multiply  half  the  cir- 
cumference by  half  the  diameter,  the  product  is  the  area ;  or  mul- 
tiply the  diameter  by  the  circumference,  and  divide  by  4;  the 
quotient  is  the  area. 

To  find  the  area  of  an  ellipse  or  oval,  multiply  the  long  di- 
ameter by  the  short  diameter ;  multiply  this  product  by  '7854, 
and  the  product  will  be  the  superficial  area  of  the  ellipse. 

To  find  the  circumference  of  an  ellipse  or  oval,  multiply  J 
the  sum  of  the  two  diameters  by  3*1416 ;  the  product  will  be  the 
circumference  of  the  ellipse. 

To  find  the  area  of  a  parallelogram,  multiply  the  length  by  the 
height  or  perpendicular  breadth. 

To  find  the  area  of  a  triangle,  multiply  the  base  by  the  perpen- 
dicular height,  and  take  half  the  product. 


THE   ENGINEEr\s  HANDY-BOOK. 


539 


To  find  the  area  of  a  trapezoid,  multiply  half  the  sum  of  the 
parallel  sides  by  the  perpendicular  distance  between  them ;  the 
product  will  be  the  area. 

To  find  the  area  of  a  quadrilateral  inscribed  in  a  circle. — From 
half  the  sum  of  the  four  sides  subtract  each  side  severally;  mul- 
tiply the  four  remainders  together  ;  the  square  root  of  the  product 
is  the  area. 

To  find  the  area  of  any  quadrilateral  figure,  divide  the  quadri- 
lateral into  two  triangles ;  the  sum  of  the  areas  of  the  triangles  is 
the  area. 

To  find  the  area  of  any  polygon,  divide  the  polygon  into  trian- 
gles and  trapezoids  by  drawing  diagonals  ;  find  the  areas  of  these, 
as  above  shown,  for  the  area. 

To  find  the  area  of  a  regular  polygon,  multiply  half  the  per- 
imeter of  the  polygon  by  the  perpendicular  drawn  from  the  centre 
to  the  centre  of  one  of  the  sides. 

To  find  the  area  of  a  sector  of  a  circle,  multiply  half  the  length 
of  the  arc  of  the  sector  by  the  radius.  Or,  multiply  the  number 
of  degrees  in  the  arc  by  the  square  of  the  radius,  and  by  '008727. 

To  find  the  area  of  a  segment  of  a  circle,  find  the  area  of  the 
sector  which  has  the  same  arc  as  the  segment;  also  the  area  of  the 
triangle  formed  by  the  radial  sides  of  the  sector  and  the  chord 
of  the  arc ;  the  difference  or  the  sum  of  these  areas  will  be  the 
area  of  the  segment,  according  as  it  is  less  or  greater  than  a  semi- 
circle. 

To  find  the  area  of  a  cycloid,  multiply  the  area  of  the  generat- 
ing circle  by  3. 

To  find  the  length  of  an  arc  of  a  parabola  cut  off*  by  a  double 
ordinate  to  the  axis.  —  To  the  square  of  the  ordinate  add  four- 
fifths  of  the  square  of  the  absciss  ;  twice  the  square  root  of  the 
sum  is  the  length  nearly. 

To  find  the  area  of  an  ellipse,  multiply  the  product  of  the  two 
axes  by  '7854. 

To  find  the  area  of  an  elliptic  segment,  the  base  of  which  is 
parallel  to  either  axis  of  the  ellipse.  —  Divide  the  height  of  the 


540 


THE   engineer's  HANDY-BOOK. 


segment  by  the  axis  of  which  it  is  a  part,  and  find  the  area  of  a 
circular  segment;  which  the  height  is  equal  to  in  this  quotient ; 
multiply  the  area  thus  found  by  the  two  axes  of  the  ellipse  suc- 
cessively ;  the  product  is  the  area. 

To  find  the  length  of  an  arc  of  a  hyperbolae  beginning  at  the 
vertex.  —  To  nineteen  times  the  transverse  axis,  add  twenty-one 
times  the  parameter  to  this  axis,  and  multiply  the  sum  by  the  I 
quotient  of  the  absciss  divided  by  the  transverse. 

To  find  the  area  of  a  hyperbola,  to  the  product  of  the  trans- 
verse and  absciss  add  five-sevenths  of  the  square  of  the  absciss, 
and  multiply  the  square  root  of  the  sum  by  twenty-one ;  to  this 
product  add  four  times  the  square  root  of  the  product  of  the  trans- 
verse and  absciss ;  multiply  the  sum  by  four  times  the  product  of  I 
the  conjugate  and  absciss,  and  divide  by  seventy-five  times  the 
transverse.    The  quotient  is  the  area  nearly. 

To  find  the  surface  of  a  prism  or  a  cylinder,  the  perimeter  of  \ 
the  end  multiplied  by  the  height  gives  the  upright  surface;  add  j 
twice  the  area  of  an  end. 

To  find  the  cubic  contents  of  a  prism  or  a  cylinder,  multiply 
the  area  of  the  base  by  the  height.  ] 

To  find  the  surface  of  a  pyramid  or  a  cone,  multiply  the  per-  . 
imeter  of  the  base  by  half  the  slant  height,  and  add  the  area  of  j 
the  base.  < 

To  find  the  cubic  contents  of  a  pyramid  or  a  cone,  multiply  the  j 
area  of  the  base  by  one-third  of  the  perpendicular  height. 

To  find  the  surface  of  a  frustum  of  a  pyramid  or  a  cone,  mul- 
tiply the  sum  of  the  perimeters  of  the  ends  by  half  the  slant 
height,  and  add  the  areas  of  the  ends. 

To  find  the  cubic  contents  of  a  frustum  of  a  pyramid  or  a 
cone,  add  together  the  areas  of  the  two  ends,  and  the  mean  pro- 
portional between  them  (that  is,  the  square  root  of  their  pro- 
duct), and  multiply  the  sum  by  one-third  of  the  perpendicular 
height. 

To  find  the  cubic  contents  of  a  segment  of  a  sphere,  from  three 
times  the  diameter  of  the  sphere  subtract  twice  the  height  of  the 


THE   engineer's  HANDY-BOOK. 


541 


segment;  multiply  the  difference  by  the  square  of  the  height, 
and  by  -5236. 

To  find  the  cubic  contents  of  a  frustum  or  zone  of  a  sphere.  — 
To  the  sum  of  the  squares  of  the  radii  of  the  ends  add  one-third 
of  the  square  of  the  height ;  multiply  the  sum  by  the  height  and 
by  1-5708. 

To  find  the  cubic  contents  of  a  spheroid,  multiply  the  square 
of  the  revolving  axis  by  the  fixed  axis  and  by  '5236. 

To  find  the  cubic  contents  of  a  segment  of  a  spheroid.  —When 
the  base  is  parallel  to  the  revolving  axis,  multiply  the  difference 
between  thrice  the  fixed  axis  and  double  the  height  of  the  segment 
by  the  square  of  the  height,  and  the  product  by  -5236. 

To  find  the  cubic  contents  of  a  wedge.  — To  twice  the  length  of 
the  base  add  the  length  of  the  edge ;  multiply  the  sum  by  the 
breadth  of  the  base,  and  by  one-sixth  of  the  height. 

To  find  the  cubic  contents  of  a  prismoid  (a  solid  of  which  the 
two  ends  are  dissimilar,  but  parallel  plane  figures  of  the  same 
number  of  sides).— To  the  sum  of  the  areas  of  the  two  ends,  add 
four  times  the  area  of  a  section  parallel  to  and  equally  distant 
from  both  ends ;  and  multiply  the  sum  by  one-sixth  of  the  length. 

To  find  the  surface  of  a  sphere,  multiply  the  square  of  the  di- 
ameter by  3*1416. 

To  find  the  curve  surface  of  any  segment  or  zone  of  a  sphere,  ^ 
multiply  the  diameter  of  the  sphere  by  the  height  of  the  zone  or 
segment  and  by  3*1416. 

To  find  the  cubic  contents  of  a  sphere,  multiply  the  cube  of 
the  diameter  by  '5236. 

To  find  the  cubic  contents  of  a  parabolic  conoid,  multiply  the 
area  of  the  base  by  half  the  height. 

To  find  the  cubic  contents  of  a  frustum  of  a  parabolic  conoid, 
multiply  half  the  sum  of  the  areas  of  the  two  ends  by  the  height 
of  the  frustum. 
46 


542  THE-  ENGINEER'S  HANDY-BOOK. 


Signification  of  Signs  Used  in  Calculations. 

=  signifies  Equality,  as  3  added  to  2  =  5. 

+       "       Addition,  "    4  4-2  =  6. 

—       "       Subtraction,  "    7  —  4  3. 

X       "      Multiplication,         "    6  x  2  =  12. 

-i-       "       Division,  "    16      4  =  4. 

:  :  :  :  "       Proportion,  "    2  is  to  3  so  is  4  to  6. 

v/       "       Square  Root,  "    ^/16  =  4. 

y      "       Cube  Root,  "    ^64  =  4. 

3'        "       3  is  to  be  squared,     "    3'^  =  9. 

3'       "       3  is  to  be  cubed,       "    3'  =  27. 

2+5x4  =  28  signifies  that  two,  three,  or  more  numbers 

are  to  be  taken  together,  as  2  +  5  =  7,  and 

4  times  7  =  28. 

+,  plus,  means  that  the  number  after  it  is  to  be  added  to  the 
number  before  it ;  thus,  5  +  4  are  9. 

— ,  minus,  means  that  the  number  after  it  is  to  be  subtracted 
from  the  number  before  it ;  thus,  5  —  4  is  1. 

X ,  multiplied  by,  means  that  the  number  before  it  is  to  be  mul- 
tiplied by  the  number  after  it ;  thus,  9  X  3  are  27. 

divided  by,  means  that  the  number  before  it  is  to  be  divided 
by  the  number  after  it ;  thus,  9  -r-  3  are  3. 

— ,  equal  to,  means  that  the  quantity  after  it  is  of  the  same 
value  as  the  quantity  before  it;  thus,  5  +  6  =  11. 


The  Cipher. 

The  term  Cipher  has  various  meanings.  It  is  usually  applied 
to  the  figure  0,  which  is  equivalent  to  zero,  or  nothing.  It  also 
means  a  combination  or  intertexture  of  letters,  as  the  initials  of 
a  name,  the  several  letters  being  intertwined  so  as  to  form  one 
figure.  The  word  cipher  also  means  secret  writing;  the  proper 
name  for  which,  however,  is  cryptogram. 


THE  ENGINEER'S  HANDY-BOOK. 

TABLE 


OF  DIAMETERS  AND  AREAS  OF  SMALL  CIRCLES. 


DiAM. 

Area. 

J^IAM. 

Area. 

DiAM. 

Area. 

•001 

•0000008 

•027 

•0005726 

•0625 

•0030680 

•009 

•OOOOOrJl 

•028 

•0006158 

•065 

•0033183 

•0000071 

•029 

•0006605 

•070 

•0038485 

•004 

•0000126 

•030 

•0007069 

•075 

•0044179 

•005 

•0000196 

\J \J  \J  \J  A.  fJ  \J 

•031 

•0007548 

•080 

•0050266 

•006 

•0000283 

•03125 

•0007670 

•085 

•0056745 

•007 

•0000385 

•032 

•0008043 

•090 

•0063617 

'008 

•0000503 

•033 

•0008553 

•095 

•0070882 

•009 

•0000639 

•034 

•0009079 

•100 

•0078540 

•010 

•0000785 

•035 

•0009621 

•125 

•0122719 

•Oil 

•0000950 

•036 

•0010179 

•150 

•0176715 

•012 

0001131 

•037 

•0010752 

•200 

•0314159 

•013 

•0001327 

•038 

•0011341 

•250 

•0490875 

•014 

•0001539 

•039 

•0011946 

•300 

•0706858 

•015 

0001767 

•040 

•0012566 

•350 

•0962115 

•015625 

•O0O1917 

V/  *J  v/  -1.  t/  J.  1 

•041 

•0013203 

•400 

•1256637 

•016 

•0002016 

•042 

•0013855 

•450 

•1590435 

•017 

•0002270 

•043 

•0014522 

•500 

•1963495 

•018 

•0002545 

•044 

•0015205 

•550 

•2375835 

•019 

•0002835 

•045 

•0015904 

•600 

•2827440 

•020 

•0003142 

•046 

•0016619 

•650 

•3318315 

•021 

•0003464 

•047 

•0017349 

•700 

•3848441 

•022 

•0003801 

•048 

•0018096 

•750 

1  ^4417875 

•023 

•0004155 

•049 

•0018857 

•800 

•5026548 

•024 

•0004524 

•050 

•0019635 

•850 

•5674515 

•025 

,  ^0004909 

•055 

•0023758 

•900 

•6361725 

•026 

1  -0005309 

•060 

•0028274 

•950 

•7088235 

644 


THE   ENGINEER'S  HANDY-BOOK. 


TABLE 

CONTAINING  THE  DIAMETERS,  CIRCUMFERENCES,  AND  AREAS  OF 
CIRCLES  FROM         O:^  AN  INCH  TO  100  INCHES,  ADVANCING  BY 
of  an  inch  up  to  10  INCHES,  AND  BY  J  OP  AN  INCH  FROM 
10  TO  100  INCHES. 


DiAM. 

CiRCUM. 

Area. 

DiAM. 

CiRCUM. 

Area. 

Inch. 

Inch. 

.1963 

.0030 

7.6576 

4.6664 

i 

.3927 

.0122 

i 

7.8540 

4.9087 

t 

.5890 

.0276 

^> 

8.0503 

5.1573 

.7854 

.0490 

8.2467 

5.4119 

5 

IS 

.9817 

.0767 

H 

8.4430 

5.6727 

3 
8 

1.1781 

.1104 

ii 
4 

8.6394 

5.9395 

1.3744 

.1503 

1  3 

8.8357 

6.2126 

t 

1.5708 

.1963 

9.0321 

6.4918 

9 

1 

1.7671 

.2485 

9.2284 

6.7772 

1.9635 

.3068 

3 

9.4248 

7.0686 

2.1598 

.3712 

9.6211 

7.3662 

2.3562 

.4417 

t 

9.8175 

7.6699 

1  3 

1 

2.5525 

.5185 

10.0138 

7.9798 

2.7489 

.6013 

i 

10.2120 

8.2957 

H 

2.9452 

.6903 

❖ 
f 

10.4065 

8.6179 

1 

3.1416 

.7854 

10.6029 

8.9462 

i 

3.3379 

.8861 

i 

10.7992 

9.2806 

3.5343 

.9940 

10.9956 

9.6211 

3.7306 

1.1075 

9 
1 

11.1919 

9.9678 

3.9270 

1.2271 

11.3883 

10.3206 

4.1233 

1.3529 

11.5846 

10.6796 

3 
8 

4.3197 

1.4848 

11.7810 

11.0446 

4.5160 

1.6229 

ii 

11.9773 

11.4159 

t 

4.7124 

1.7671 

i 

12.1737 

11.7932 

4.9087 

1.9175 

if 

12.3700 

12.1768 

5.1051 

2.0739 

4 

12.5664 

12.5664 

1  1 

5.3014 

2.2365 

i 

12.7627 

12.9622 

f 

5.4978 

2.4052 

12.9591 

13.3640 

5.6941 

2.5801 

A 

13.1554 

13.7721 

¥ 

5.8905 

2.7611 

i 

13.3518 

14.1862 

if 

6.0868 

2.9483 

t 

13.5481 

14.6066 

2 

6.2832 

3.1416 

13.7445 

15.0331 

t 

6.4795 

3.3411 

13.9408 

15.4657 

6.6759 

3.5465 

i 

14.1372 

15.9043 

6.8722 

3.7582 

9 

14.3335 

16.3492 

7.0686 

3.9760 

Y 

8 

14.5299 

16.8001 

7.2640 

4.2001 

14.7262 

17.2573 

t 

7.4613 

4.4302 

14.9226 

17.7205 

THE   ENGINEEirs  HANDY-BOOK. 


545 


TABLE  —  (Continued) 


CONTAINING  THE  DIAM.,  CIRCUMFERENCES,  AND  AREAS  OF  CIRCLES. 


DiAM. 

CiRCUM. 

Area. 

DlAM. 

CiRCUM. 

Area. 

Inch 

I  h 

7 

15.1189 

18.1900 

23.3656 

43.4455 

15.3153 

18.6655 

t 

23.5620 

44.1787 

15.5716 

19.1472 

9 

Y 

8 

23.7583 

44.9181 

5 

15.7080 

19.6350 

23.9547 

45.6636 

15.9043 

20.1290 

24.1510 

46.4153 

16.1007 

20.6290 

4 

24.3474 

47.1730 

16.2970 

21.1252 

4-4 
? 

24.5437 

47.9370 

t 

16.4934 

21.6475 

24.7401 

48.7070 

A- 

16.6897 

22.1661 

H 

8 

24.9364 

49.4833 

16.8861 

22.6907 

25.1328 

50.2656 

17.0824 

23.2215 

8 

25.3291 

51.0541 

2 

17.2788 

23.7583 

25.5255 

51.8486 

9 

17.4751 

24.3014 

25.7218 

52.8994 

17.6715 

24.8505 

t 

4 

25.9182 

53.4562 

1 1 

17.8678 

25.4058 

8 

26.1145 

54.2748 

Y 

4 

18.0642 

25.9672 

26.3109 

55.0885 

H 

18.2605 

26.5348 

26.5072 

55.9138 

18.4569 

27.1085 

? 

2 

26.7036 

56.7451 

■3-4 
6 

18.6532 

27.6884 

9 

1 

8 

26.8999 

57.5887 

18.8496 

28.2744 

27.0963 

58.4264 

]  9.0459 

28.8665 

1 1 

r¥ 

27.2926 

59.7762 

t 

19.2423 

29.4647 

4 

27.4890 

60.1321 

A 

19.4386 

30.0798 

16 

27.6853 

60.9943 

A- 

19.6350 

30.6796 

7 

8 

27.8817 

61.8625 

19.8313 

31.2964 

1  5 

T¥ 

28.0780 

62.7369 

¥ 

20.0277 

31.9192 

9 

28.2744 

63.6174 

i 
2 

20.2240 

32.5481 

1 

Y 

8 

28.4707 

64.5041 

20.4204 

33.1831 

28.6671 

65.3968 

20.6167 

33.8244 

28^8634 

66^2957 

20.8131 

34.4717 

t 

4 

29.0598 

67.2007 

2L0094 

35.1252 

TF 

29.2561 

68.1 120 

4 

21.2058 

35.7847 

8 

29.4525 

69.0293 

21.4021 

36.4505 

29.6488 

69.9528 

21  5Q85 

.^7  1224  i 

? 

2 

9Q  8452 

70.8823 

1  5 
T¥ 

21.7948 

^7  8005  1 

■X 

? 

'  71.8181 

7 

21^9912 

38.4846  i 

30.2379 

72.7599 

t 

22.1875 

39.1749 

30.4342 

73.7079 

22.3839 

39.8713 

4 

30.6306 

74.6620 

t 

22.5802 

40.5469 

1  3 

i 

30.8269 

75.62l>3 

22.7766 

41.2825 

31.0233 

76.5887 

22.9729 

41.9974 

31.2196 

77.5613 

t 

23.1693 

42.7184 

10 

31.4160 

78.5400 

46*  2K 


THE   engineer's  IIANDY-BOOK. 

T  A  B  L  E  —  ( Continued) 


CONTAINING  THE  DIAM.,  CIRCUMFERENCES,  AND  AREAS  OF  CIRCLES. 


DiAM. 

CiRCUM. 

• 

Area. 

DiAM. 

CiRCUM. 

Area. 

Inch. 

Inch. 



31.8087 

80.5157 

8 
8^ 

48.3021 

185.6612 

i 

32.2014 

82.5160 

I 

48.6948 

188.6923 

32.5941 

84.5409 

5 
8 

49.0875 

191.7480 

1 

52.9868 

86.5903 

4 

49.4802 

194.8282 

33.3795 

88.6643 

49.8729 

197.9330 

3 
4 

33.7722 

90.7627  ! 

16 

50.2656 

201.0624 

7 

■ft 

34.1649 

92.8858  1 

50.6583 

204.2162 

11 

34.5576 

95.0334  1 

i 

1 

51.0510 

207.3946 

34.9503 

97.2053  i 

51.4437 

210.5976 

\ 

35.3430 

99.4021 

i 
f 

51.8364 

213.8251 

"8 

35.7357 

101.6234 

52.2291 

217.0772 

36.1284 

103.8691  I 

1 

52.6218 

220.3537 

5 
3 

36.5211 

106.1394  1 

7 

53.0145 

223.6549 

4 

36.9138 

108.4342 

17 

53.4072 

226.9806 

7 

"S" 

37.3065 

110.7536 

53.7999 

230.3308 

12 

37.6992 

113.0976 

54.1926 

233.7055 

38.0919 

115.4660 

f 

54.5853 

237.1049 

1 

38.4846 

117.8590 

54.9780 

240.5287 

3 

38.8773 

120.2766 

55.3707 

243.9771 

39.2700 

122.7187 

4 

55.7634 

247.4500 

39.6627 

125.1854 

i 

56.1561 

250.9475 

i 

40.0554 

127.6765 

18 

56.5488 

254.4696 

7 

40.4481 

130.1923 

i 

56.9415 

258.0161 

13 

40.8408 

132.7326 

\ 

57.3342 

261.5872 

I 

41.2338 

135.2974 

3 
8^ 

57.7269 

265.1829 

i 

41.6262 

137.8867 

1 

58.1196 

268.8031 

3 
"8 

42.0189 

140.5007 

58.5123 

272.4479 

i 

42.4116 

143.1391 

58.9056 

276.1171 

1 

42.8043 

145.8021 

7 

■g" 

59.2977 

279.8110 

3 

43.1970 

148.4896 

19 

59.6904 

283.5294 

43.5897 

251.2017 

4 

60.0831 

287.2723 

14 

43.9824 

.53.9384 

4 

60.4758 

291.0397 

44.3751 

156.6995 

60.8685 

294.8312 

i 

44.7676 

159.4852 

■1 

61.2612 

298.6483 

45.1605 

162.2956 

5 
g- 

61.6539 

302.4894 

45.5532 

165.1303 

3 

a. 

62.0466 

306.3550 

45.9459 

167.9896 

i 

62.4393 

310.2452 

46.3386 

170.8735 

20 

62.8320 

314.1600 

1 

46.7313 

173.7820 

63.2247 

318.0992 

15 

47.1240 

176.7150 

i 

i 

63.6174 

322.0630 

i 

47.5167 

179.6725 

64.0101 

326.0514 

i 

47.9094 

182.6545 

64.4028 

330.0643 

THE    engineer's   HANDY-BOOK.  547 
T  A  B  L.  Fi  —  iOmtinued) 


CONTAINING  THE  DIAM.,  CIRCUMFERENCES,  AND  AREAS  OF  CIRCLES. 


DiAM. 

CiRCUM. 

Area. 

DiAM. 

CiRCUM. 

Area. 

Inch. 

Inch. 

■  - 

64.7955 

334.1018 

i 

_ 

81.2889 

525.8375 

65.1882 

338.1637 

26 

81.6816 

530.9304 

65.5809 

342.2503 

I 

82.0743 

536.0477 

21 

65.7936 

346.3614 

i 

82.4670 

541.1896 

X 
o 

66.3663 

350.4970 

. 

82.8597 

546.3561 

I 
i 

8 

66.7590 

354.6571 

i 

83.2524 

551.5471 

67.1517 

358.8419 

i 

83.6451 

556.7627 

i 

67.5444 

363.0511 

S 

84.0378 

562.0027 

67.9371 

367.2849 

84.4305 

567.2674 

'  1 

68.3298 

371.5432 

27 

84.8232 

572.5566 

i 

68.7225 

375.8261 

•  I 

t 

85.2159 

577.8703 

22 

69.1152 

380.1336 

i 

85.6086 

583.2085 

8 

69.5079 

384.4655 

i 

. 

86.0013 

588.5714 

I 
i 

4 

8 

69.9006 

388.8220 

1 

86.3940 

593.9587 

70.2933 

393.2031 

I 

86.7867 

599.3706 

1 

70.6860 

397.6087 

i 

87.1794 

604.8070 

8 

71.0787 

402.0388 

i 

87.5721 

610.2680 

1 

71.4714 

406.4935 

28 

87.9648 

615.7536 

71.8641 

41o!9728 

i 

\ 

88.3575 

621.2636 

23 

72.2568 

415!4766 

88.7502 

626.7982 

8 

72.6495 

420.0049 

1 

89.1429 

632.3574 

73.0422 

424.5577 

89.5356 

637.9411 

8 

73.4349 

429.1352 

89.9283 

643.5494 

73.8276 

433.7371 

90.3210 

649.1821 

74.2203 

438.3636 

90.7137 

654.8395 

74.6130 

443.0146 

29 

91.1064 

660.5214 

7 
8 

75.0057 

447.6992 

i 

91.4991 

666.2278 

24 

75.3984 

452.3904 

i 

91.8918 

671.9587 

0 

75.7911 

457.1150 

i 

: 

92.2845 

677.7143 

4 

3 
8 

76.1838 

461.8642 

92.6772 

683.4943 

76.5765 

466.6380 

93.0699 

689.2989 

2 

76!9692 

47l!4363 

* 

93.4626 

695.1280 

77.3619 

476^2592 

i 

93.8553 

700.9817 

77.7546 

481  1065 

30 

94.2480 

706.8600 

7 

78!l473 

485  9785 

94.6407 

712.7627 

25 

78.*5400 

490.8750 

i 

95.0334 

718.6900 

i 

78.9327 

495.7960 

95.4261 

724.6419 

79.3254 

500.7415 

i 

95.8188 

730.6183 

i 

79.7181 

505.7117 

i 

96.2115 

736.6193 

80.1108 

510.7063 

1 

96.6042 

742.6447  i 

80.5035 

515.7255 

i 

96.9969 

748.6948 

i  1 

80.8962 

620.7692 

31 

97.3896 

75^.7694 

THE    ENGINEER'S  HANDY-BOOK. 
TABLE  —  (Continued) 


CONTAINING  THE  DIAM.,  CIRCUMFERENCES,  AND  AREAS  OP  CIRCLES. 


DiAM. 

CiRCUM. 

Area. 

DiAM. 

CiRCUM. 

Area. 

Inch. 

Inch. 

760  8685 

3 

8 

114.2757 

1039  1946 

766  9921 

i 

¥ 

114  6684 

1 046  3941 

X  V/ xV/.C»»7  JCX 

8 

5fi77 

773.1404 

115  061 1 

X  X  t/.V/VJX  X 

1 053  5281 

i 

8 

779  3131 

f 

1 1 5  4538 

1 060  731 7 

x.\j\j\j,  1  ox « 

99.3531 

785.5104 

7 

8 

115.8465 

1067  9599 

i 

99  7458 

791  7322 

1  ex . (  tJZj^ 

37 

1 1 6  2.392 

1075  2126 

xv<  c^x 

7 

8 

1 00  1 385 

797  9786 

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X  X  W.'Jc/X  «7 

1 082  4898 

X  V/ *J  *J .  i  <J  t7 

32 

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804.2496 

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XVv-/»7.l  0  XfJ 

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100  9240 

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X V/«7  <  .X  X  <  V 

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101  31fifi 

816  8650 

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117  8100 

J  X 1  .ox  w 

1 1 04  4687 

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823  2096 

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X  X  O.xJV^  1 

1111.8441 

1 

2 

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829  5787 

f 

118  5954 

1119  2440 

X  X  X  i7  .  ^(Tt'l  V/ 

102.4947 

835.9724 

118  9881 

X  XO.  i700X 

1 1 26  6685 

102  8874 

842^3905 

38 

1 1 9  3808 

1 1 .34  1 1 76 

X  X  O^.X  X  1  \J 

7 

¥ 

1 03  2801 

848.8333 

1 

8 

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4 

1 1 9  77.35 

X  X  i/.  <  1  *jU 

1141  5911 

XX^X.t^t7XX 

33 

103.6728 

855.3006 

120  16H2 

1 149  0892 

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XXt/\J.V/XXi7 

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120  9516 

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XX  #  X.I  OV»/ 

1 05  2436 

881.4151 

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894  6196 

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1 22  5224 

1 1 94  59.34 

X  X  C7rr.Ui7c>Tt 

7 

106  4217 

901.2587 

1 

8 

1 22  91 51 

1 202  2633 

34 

106  8144 

X  v/\J . 0  X  X  X 

907  9224 

JL 
? 

4 

8 

1 93  3078 

1 209  9577 

1 

¥ 

107  2071 

914  6105 

1 23  7005 

1217  6768 

XjUX  1  .U  1  uo 

JL 
4 

1 07  5998 

921  3232 

I 
2 

¥ 

1 24  0932 

1 225  4203 

3 
8 

107  9925 

928  0605 

1 24  4859 

1 2.33  1 884 

1 

2 

1 08  .3852 

9.34  8223 

f 

1 24  9787 

1240  9810 

108  7779 

941  6086 

X 
8 

195  971 3 

1248  7989 

4 

109  1706 

948  41 95 

40 

1 95  fi640 

1 256  6400 

7 

¥ 

1 09  5633 

955  2550 

1 

¥ 

1 26  0567 

1 264  5062 

35 

1 09  9560 

962  1 1 50 

1 
4 

1 9fi  44Q4 

1  979  ^970 

1 

8 

1 1 0  3487 

X  X  V.lJ  1 

968  9995 

8 

126.8421 

1980  3194 

X 
? 

110.7414 

975  Q085 

1 

¥ 

1  97  9348 

1 988  9^9^ 

3 
8 

111.1341 

982  8422 

1 97  fi975 

199fi  91fi8 

1 

"2 

lll!5268 

989.8003 

128.0202 

1304.2057 

1 

111.9195 

996.7830 

128.4129 

1312.2193 

i 

112.3122 

1003.7902 

41 

128.8056 

1320.2574 

7 

¥ 

112.7049 

1010.8220 

1 

129.1983 

1328.3200 

36 

113.0976 

1017.8784 

1 

129.5910 

1336.4071 

i 

113.4903 

1024.9592 

3 
8 

129.9837 

1344.5189 

i 

113.8830 

1032.0646 

i 

130.3764 

1352.6551 

THE   ENGTNEER^S    HANDY-BOOK.  ^49 
T  A  B  L  E  —  (Cbw/mM«<f) 


CONTAININQ  THE  DIAM.,  CIRCUMFERENCES,  AND  AREAS  OF  CIRCLEa 


DiAM. 

CiRCUM. 

Area. 

DiAM. 

CiRCIIM. 

Area. 

Inch. 

Inch. 

130.7691 

1360.8159 

i 

147.2625 

1725.7324 

f 

131.1618 

1369.0012 

47 

147.6552 

1734.9486 

8" 

131.5545 

1377.2111 

148.0479 

1744.1893 

42 

131.9472 

1385.4456 

I 
1 

148.4406 

1753.4545 

i 

132.3399 

1393.7045 

148.8333 

1762.7344 

132.7326 

1401.9880 

149.2260 

1772.0587 

1 

133.1253 

1410.2961 

i 

149.6187 

1781.3976 

i 

i 

133.5180 

1418.6287 

f 

150.0114 

1790.7610 

133.9107 

1426.9859 

"g" 

150.4041 

1800.1490 

t 

134.3034 

1435.3675 

48 

150.7968 

1809.5616 

i 

134.6961 

1443.7738 

i 

151.1895 

1818.9986 

43 

135.0888 

1452.2046 

i 

f 

151.5822 

1828.4602 

*  i 

135.4815 

1460.6599 

151.9749 

1837.9364 

i 

135.8/42 

1469.1397 

152.3676 

1847.4571 

1 

136.2669 

1477.6342 

152.7603 

1856.9924 

i 

136.6596 

1486.1731 

f 

153.1530 

1868.5521 

1 

137.0523 

1494.7266 

i 

153.5457 

1876.1365 

i 

137.4450 

1503.3046 

49 

153.9384 

1885.7454 

7 

i 

137.8377 

1511.9072 

i 

154.3311 

1895.3788 

A  A 

44 

138.2304 

1520.5344 

i 
i 

154.7238 

1905.0367 

138.6231 

1529.1860 

155.1165 

1914.7093 

139.0158 

1537.8622 

155.5092 

1924.4263 

1 

139.4085 

1546.5530 

1 

155.9019 

1934.1579 

i 

139.8012 

1555.2883 

3. 
4 

156.2946 

1943.9140 

t 

140.1939 

1564.0382 

¥• 

156.6873 

1953.6947 

J 

140.5866 

1572.8125 

50 

157.0800 

1963.5000 

7 

140.9793 

1581.6115 

i 

157.4727 

1973.3297 

45 

141.3720 

1590.4350 

i 

1 

157.8654 

1983.1840 

141.7647 

1599.2830  . 

158.2581 

1993.0529 

J 

142.1574 

1608.1555 

i 
1 

158.6508 

2002.9663 

142.5501 

1617.0427 

159.0435 

2012.8943 

142.9428 

1625.9743 

3. 
4 

159.4362 

2022.8467 

t 

143.3355 

1634.9205 

i 

159.8289 

2032.8238 

143.7382 

1643.8912 

51 

160.2216 

2042.8254 

7 

■g" 

144.1209 

1652.8865 

1 

8 

160.6143 

2052.8515 

46 

144  51  ."^n 

4 

lOi.UU/  u 

1 

J 

144.9063 

1670.9507 

3. 
8 

161.3997 

2072.9764 

i 

145.2990 

1680.0196 

1 

f 

161.7924 

2083.0771 

i 

145.6917 

1689.1031 

162.1851 

2093.2014 

i 

146.0844 

1698.2311 

4 

i 

162.5778 

2103.3502 

1 

146.4771 

1707.3737 

162.9705 

2113.5236 

a 

146.8698 

1716.5407 

52 

163.3632 

2123.7216 

550  THE  engineer's  handy-book. 

T  A  B  Ij  E  —  ( Continued) 


CONTAINING  THE  DIAM.,  CIRCUMFERENCES,  AND  AREAS  OF  CIRCLES. 


DiAM. 

CIRCUM. 

t 

Area. 

lA  . 

CiRCUM. 

Area, 

Inch. 

Inch. 

i 

163.7559 

2133.9440 

3 
8 

180.2493 

2585.4509 

i 

164.1486 

2144.1910 

180.6423 

2596.7287 

8 

164.5413 

2154.4626 

i> 

8 

181.0347 

2608.0311 

1 

i 

164.9340 

2164.7587 

a 

4 

181.4274 

2619.3580 

165.3267 

2175.0794 

t 

181.8201 

2630.7095 

i 

165.7194 

2185.4245 

58 

182.2128 

2642.0856 

7 

166.1121 

2195.7943 

i 

182.6055 

2653.4861 

53 

166.5048 

2206.1886 

i 

i 

182.9982 

2664.9112 

i 

166.8975 

2216.6074 

183.3909 

2676.3609 

i 

167.2902 

2227.0507 

i 

183.7836 

2687.8351 

167.6829 

2237.5187 

184.1763 

2699.3338 

i 

168.0756 

2248.0111 

184  5690 

2710.8571 

1 

168.4683 

2258.5281 

7 
8 

184.9617 

2722.4050 

i 

168.8610 

2269.0696 

59 

185.3544 

2733.9774 

i 

169.2537 

2279.6357 

i 

185.7471 

2745.5743 

54 

169.6464 

2290  2264 

i 

3 
8 

186.1398 

2757.1957 

i 

170.0391 

2300.8415 

186.5325 

2768.8418 

i 

170.4318 

2311.4812 

f 

186.9252 

2780.5123 

f 

170.8245 

2322.1455 

187.3179 

2792.2074 

1 

171.2172 

2332.8343 

3. 
4 

187.7106 

2803.9270 

171.6099 

2343.5477 

7 

¥ 

188.1033 

2815.6712 

f 

172.0026 

2354.2855 

CO 

188.4960 

2827.4400 

172.3593 

2365.0480 

i 

188.8887 

2839.2332 

55 

172.7880 

2375.8350 

i 

189.2814 

2851.0510 

i 

173.1807 

2386.6465 

3 
8 

189.6741 

2862.8934 

173.5734 

2397.4825 

i 

190.0668 

2874.7603 

8 

173.9661 

2408.3432 

5 
8 

190.4595 

2886.6517 

174.3588 

2419.2283 

2. 
4 

¥ 

190.8522 

2898.5677 

174.7515 

2430.1833 

191.2419 

2910.5083 

i 

175.1442 

2441.0772 

61 

191.6376 

2922.4734 

7 

175.5369 

2452.0310 

i 

192.0303 

2934.4630 

56 

175.9296 

2463.0144 

1 

4 

192.4230 

2946.4771 

i 

176.3323 

2474.0222 

i 

192.8157 

2958.5139 

i 

1 

176.7150 

2485.3546 

i 

193.2084 

2970.5791 

177.1077 

2496.1116 

1 

193.6011 

2982.6669 

1 

177.5004 

2507.1931 

i 

193.9931 

177.8931 

2518.2992 

7 

8 

194.3865 

3006.9161 

i 

178.2858 

2529.4297 

62 

194.7792 

3019.0776 

i 

178.6785 

2543.5849 

i 

195.1719 

3031.2635 

57 

179.0712 

2551.7646 

i 

195.5646 

3043.4740 

4 

179.4639 

2562.9688 

3 

195.9573 

3055.7091 

179.8566 

2574.1975 

i 

196.3500 

3067.9687 

THE    ENOIXEER^S  HANDY-BOOK. 
TABLE  —  (Continued) 


CONTAINING  THE  DIAM.,  CIRCUMFERENCES,  AND  AREAS  OP  CIRCLES. 


DiAM. 

CiRCUM. 

Area. 

DiAM. 

CiRCUM. 

Area. 

Inch. 

Inch. 

196.7427 

3080.2529 

i 

213.2361 

3618.3300 

* 

197.1354 

3092.5615 

68 

213.6288 

3631.6896 

i 

197.5281 

3104.8948 

i 

214.0215 

3645.0536 

63 

197.9208 

3117.2526 

\ 

214.4142 

3658.4402 

i 

198.3135 

3129.6349 

1 

214.8069 

3671.8554 

i 

198.7062 

3142.0417 

215.1996 

3685.2931 

199.0989 

3154  4732 

215.5923 

3698.7554 

i 

1 

199.4916 

3166.9291 

f 

215.9850 

3712.2421 

199.8843 

3179.4096 

¥ 

216.3777 

3725.7535 

i 

200.2770 

3191.9146 

69 

216.7704 

3739.2894 

i 

200.6697 

3204.4442 

i 

217.1631 

3752.8498 

64 

201.0624 

3216.9984 

f 

217.5558 

37 66.4327 

4 

201.4551 

3229.5770 

217.9485 

3780.0443 

i 

t 

201.8478 

3242.1782 

218.3412 

3793.6783 

202.2405 

3254.8080 

1 

218.7339 

3807.3369 

i 

202.6332 

3267.4603 

f 
1 

219.1266 

3821.0200 

1 

203.0259 

3280.1372 

219.5193 

3834.7277 

t 

203.4186 

3292.8385 

70 

219.9120 

3848.4600 

7 

203.8113 

3305.5645 

4 

220.3047 

3862.2167 

65 

204.2040 

3318.3151 

1 

220.6974 

3875.9960 

204.5917 

3331.0900 

8 

221.0901 

3889.8039 

1 

OA  A   f\Of\  A 

204.9894 

3343.8875 

221.4828 

3903.6343 

1 

205.3821 

3356.7137 

f 

221.8755 

3917.4893 

1 

205.7748 

3369.5623 

4 

i 

222.2682 

3931.3687 

t 

206.16/5 

3382.4355 

222.6609 

3945.2728 

1 

206.5602 

3395.3332 

71 

223.0536 

3959.2014 

1- 

206.9529 

3408.2555 

4 

223.4463 

3973.1545 

66 

O  Arr  o  /«  ^  /» 

207.34o6 

3421.2024 

i 

223.8390 

3987.1301 

i 

207.7383 

3434.1737 

224.2317 

4001.1344 

i 

OAO  1  O  1  /\ 

208.1310 

3447.1676 

224.6244 

4015.1611 

208.5237 

3468.1901 

225.0171 

4029.2124 

OAO  t\t  n  A 

208.9164 

3473.2351 

i 

225.4098 

4043.2882 

5 
t 

i 

209.3091 

3486.3047 

X 

225.8025 

4057.3886 

209.7018 

3499.3987 

72 

226.1952 

4071.5136 

7 

i 

210.0945 

3512.5174 

4 

226.5879 

4085.6631 

67 

210.4872 

4 

1 

4 

21o!8799 

3538.8283 

227.3733 

4114.0356 

i 

211.2726 

3552.0185 

i 

1 

227.7660 

4128.2587 

i 

211.6653 

3565.2374 

228.1587 

4142.5064 

212.0580 

3578.4787 

4 

228.5514 

4156.7785 

1 

212.4507 

3591.7446 

228.9441 

4171.0753 

212.8434 

3605.0350 

73  1 

229.3368 

4185.3966 

2  THE   engineer's  HANDY-BOOK. 

T  A  B  Li  E — ( Continued) 


CONTAINING  THE  DIAM.,  CIRCUMFERENCES,  AND  AREAS  OF  CIRCLES. 


DiAM. 

CiRCUM. 

Area. 

DiAM. 

CiRCUM. 

Area. 

Incli. 

Inch 

1 

41 7424 

4  * 

8 

246  222Q 

4824  42QQ 

1 

4214.1107 

I 

2 

246  61 56 

48.8Q  881 1 

8 

4228.5077 

8 

247  0088 

4855  2568 

2 

280  Q07fi 

4242.9271 

i 

247  401 0 

4870  7071 

* 

4257.3711 

7 
8 

247  7Q.87 

4886  1 820 

2.S1  6Q.S0 

4271.8396 

79 

248.1864 

4Q01  6814 

1 
8 

232.0857 

4286.3327 

8 

248.5791 

4Q17  2058 

74 

2.82  47H4 

4800  8504 

i- 
4 

248  Q718 

4Q82  7517 

1 

¥ 

2.82  8711 

481 5  .8Q26 

24Q  8645 

4Q48  89r>ft 

1 
4 

2.8.8  26.88 

482Q  Q572 

4 

24Q  7572 

4Q68  Q248 

3 
"5 

2.88  6565 

4.844  5505 

250  1 4QQ 

4Q7Q  5456 

1 

1 

8 

2.84  04Q2 

485Q  1 668 

4 

250.5426 

4005  1  QQA 

284  441 Q 

4878  8067 

8 

250  Q858 

501 0  8642 

i 

2.84  8.846 

4.888  4715 

80 

251  8280 

5026  5600 

2.85  2278 

4408  1610 

X 

8 

251  7-207 

,5042  9808 

75 

235.6200 

4417.8750 

1 
4 

1 

252.1134 

5058  0280 

1 

286  01 27 

4482  61.85 

252  5061 

5078  7Q44 

1 

286  4054 

4447  .8745 

XXX  1  ,0#  x?-J 

I 

2 

252  8Q88 

508Q  5888 

% 

2.86  7Q81 

4462  1642 

t 

258  2Q15 

51 06  4060 

i 
2 

8 

2.87  1 Q08 

4476  Q768 

4 

258  6842 

5121  24Q7 

237.5835 

44Q1  81.80 

x^t/  X  .OX  CJV 

1 

254  0769 

51.87  1178 

t^XOI  .XX<  «J 

1 

287  Q762 

4506  6742 

81 

954  46Q6 

5158  00Q4 

1 
? 

238.3689 

4521  5600 

1 

8 
i 
4 

254.8623 

5168.9260 

76 

238.7616 

4586  4704 

X    O  VJ  .  X  1  V  X 

255.2550 

5184  8651 

1 

28Q  1 548 

4551  4028 

3 
8 
I 
2 

255  6477 

5900  882Q 

J 

4 

28Q  5470 

4566  8626 

256  0404 

521 6  8281 

3 
8 

239.9397 

4581  .8486 

4 

8 

256  4881 

52.82  8.871 

2 

240.3324 

45Q6  .8571 

4 

4 

256  8258 

5248  8772 

240.7251 

4611  .8Q02 

1 
8 

257.2105 

5264  Q41 1 

3. 
4 

241.1178 

4626  4477 

82 

257.6112 

5281.0296 

1 

241.5105 

4641  .82QQ 

1 

F 

258.0039 

5297.1426 

77 

241  0082 

4656  6866 

1 
4 

258  .8Q66 

581 8  2780 

'JtJXKJtiJI  (J\J 

1 

242  2Q5Q 

4671  7678 

3 
8 

258  78Q8 

589Q  4421 

1 

4 

242.6886 

4686  Q21 5 

1 

^ 

25Q  1 890 

5.845  6287 

3 
8 

248  081 8 

4709  108Q 

8 

95Q  5747 

5.861  88Q1 

243.4740 

4717.3087 

3 
4 

259.9674 

5378.0755 

243.8667 

4732.5381 

I 

260.3601 

5394.3358 

1 

244.2594 

4747.7920 

83 

260.7528 

5410.6206 

244.6521 

4763.0705 

1 

8 

261.1455 

5426.9299 

78 

245.0448 

4778.3736 

i 

261.5382 

5443.2617 

245.4375 

4793.7012 

1 

261.9309 

5459.6222 

245.8302 

4809.0512 

i 

262.3236 

5476.0051 

THE    ENGINEER  .S  HANDY-BOOK. 

T  A  B      E  -  {Continued) 


CONTAINING  THE  DIAM.,  CIRCUMFERENCES,  AND  AREAS  OF  CIRCLES. 


DiAM. 

CiRCUM. 

Area 

DiAM. 

CiRCUM. 

Arka. 

Inch. 

Inch. 

1 

262.7163 

6492.4118 

i 

279.2097 

6203.6905 

i 

i 

263.1090 

5508.8446 

89 

279.6024 

6221.1534 

263.5017 

5525.3012 

i 

279.9951 

6238.6408 

84 

263.8944 

5541.7824 

1 

1 

280.3878 

6256.1507 

4 

264.2871 

5558.2881 

280.7805 

6273.6893 

\ 

1 

264.6798 

5574.8162 

i 

281.1732 

6291.2503 

265.0725 

5591.3730 

28 1 .5659 

6308.8351 

265.4652 

5607.9523 

2. 
4 

281.9586 

6326.4460 

265.8579 

5624.5554 

i 

282.3513 

6344.0807 

f 
i 

266.2506 

5641.1845 

90 

282.7440 

6361.7400 

266.6433 

5657.8357 

f 

283.1367 

6379.4238 

85 

267.0360 

5674.5150 

i 

283.5294 

6397.1300 

4 

267.4287 

5691.2170 

283.9221 

6414.8649 

i 

1 

267.8214 

5707.9415 

284.3148 

6432.6223 

268.2141 

5724.6947 

284.7075 

6450.4039 

268.6068 

5741.4703 

f 

285.1002 

6468.2107 

268.9997 

5758.2697 

285.4929 

6486.0418 

1 

269.3922 

5775.0952 

91 

285.8856 

6503.8974 

i 

269.7849 

5791.9445 

\ 

286.2783 

6521.7772 

86 

270.1776 

5808.8184 

i 

286.6710 

6539.6801 

\ 

270.5703 

5825.7168 

t 

287.0637 

6557.6114 

\ 

270.9630 

5842.6376 

287.4564 

6573.5651 

i 

271.3557 

5859.5871 

287.8491 

6593.5431 

271.7484 

5876.5591 

288.2418 

6611.5462 

272.1411 

5893.5549 

1 

288.6345 

6629.5736 

4 

272.5338 

5910.5767 

92 

289.0272 

6647.6258 

I 

272.9265 

5927.6224 

1 

289.4199 

6665.7021 

87 

273.3192 

5944.6926 

i 

289.8125 

6683.8010 

i 

273.7119 

5961.7873 

3 

290.2053 

6701.9286 

i 

274.1046 

5978.9045 

290.5980 

6720.0787 

1 

274.4973 

5996.0504 

290.9907 

6738.2530 

\ 
1 

274.8900 

6013.2187 

291.3834 

6756.4525 

275.2827 

6030.4108 

1 

291.7661 

6774.6763 

275.6754 

6047.6290 

93 

292.1688 

6792.9248 

oo 

276.0681 

6064.8710 

292.5615 

6811.1974 

Li  O.'iDUo 

DUoZ.  J  o  /  D 

^OOQ  JQ07 

276.8535 

6099.4287 

f 

293.3469 

6847.8167 

} 

277.2462 

6116.7422 

293.7396 

6866.1631 

i 

277.6389 

6134.0844 

294.1323 

6884.5338 

i 

278.0316 

6151.4491 

s 

294.5350 

6902.9296 

278.4243 

6169.8376 

1 

294.9177 

6921.3497 

4 

278.8170 

6186.2591 

94 

295.3104 

6939.7946 

47 


554  THE  engineer's  handy-book. 

T  A  B  L  'B— (Concluded) 


CONTAINING  THE  DIAM.,  CIRCUMFERENCES,  AND  AREAS  OF  CIRCLES. 


DiAM. 

ClRCVK. 

Abea. 

DiAM. 

CiRCUM. 

Area. 

T  I, 

T  V. 

Idcu. 

X 

8 

2Q5  7031 

6958.2636 

X 
8 

305  1 27Q 

7408  8868 

1 

¥ 

6976.7552 

1 
4 
3 

^On  5206 

7427  Q675 

8 

6995.2755 

.^05  Q1.S3 

7447  076Q 

i 

2Qfi  8812 

701  .S  818.S 

8 

OVJU.Ov/UV/ 

7466  2087 

2Q7  27 ^^Q 

70.'^2  .*^85.S 

OvU.Ut/O  f 

7485  .S648 

4 

2Q7  fifififi 

7050  Q775 

1 

.^07  0Q14 

7/S04  5460 

7 

8 

2Q8 

7060  5Q40 

I. 

.^07  4841 

7523  751 5 

f  O^O.  1  oxo 

95 

2Q8  4520 

7088.2352 

98 

.S07  8768 

7542.9818 

4 

298.8447 

7106.9005 

8 

308  26Q5 

7562.2362 

4 

299.2374 

7125.5885 

4 

4 

8 

308  6622 

7581.5132 

4 

8 

2QQ  fi.*^01 

7144  .^052 

.SOQ  054Q 

7600  818Q 

.^00  0228 

7 1  fi.S  044.S 

1 

¥ 

.qOQ  4476 

7620  1471 

1 
8 

.^00  4155 

7181  8077 

.SOQ  840.S 

i 

•SOO  8082 

tj  V/ V/ .  <_J  V  CJ 

7200  5Qfi2 

* 

.SI  0  2.S30 

7658  8771 

1  VJOv-J.tJ  fix 

7 

¥ 

i/U 

.SOI  200Q 

721Q  40Q0 

1 
t 

.SIO  6257 

7678  27Q0 

.^01  5Q.*^n 

72^8  24fifi 

QQ 

Ql  1  0184 
ox  1  .uxo^ 

7fiQ7  7056 

1 

8 

.^01  Q8fi.S 

7-^57  108.S 

311.4111 

7717  1563 

1  #  X  f  .  X  tJViO 

i 

302.3790 

7275.9926 

1 

31L8038 

7736.6297 

302.7717 

7294.9056 

f 

312.1965 

7756.1318 

i 

1 

303.1644 

7313.8411 

i 

-1 

312.5892 

7775.6563 

303.5571 

7332.8008 

312.9819 

7795.2051 

303.9498 

7351.7857 

3 

313.3746 

7814.7790 

304.3425 

7370.7949 

313.7673 

7834.3772 

97 

304.7352 

7389.8288 

100 

314.1600 

7854.0000 

Fop  circumfepence  of  circles  larger  than  those  given  in  the' 
table,  multiply  the  diameter  by  3,1416. 

Example.— Diameter  101''  x  3,1416  =  317,3016. 

Fop  apeas  larger  than  those  in  the  table,  multiply  the  square 
of  the  diameter  by  the  decimal  .7854. 

Example— 101  inchesxlOl  ==10201  x. 7854  =  8011,86  sq.  in. 


THE   ENGINEEr\s    HANDY-BOOK.  555 


TABLE 

OF  LOGARITHMS  OF  NUMBERS  FROM  0  TO  1000.^ 


No 

0 

1 

3 

4 

5 

6 

7 

8 

9 

Prop. 

0 

0 

00000 

30103 

47712 

60206 

69897 

77815 

84510 

90309 

95424 

415 

10 

00000 

00432 

00860 

01283 

01703 

02118 

02530 

02938 

03342 

03742 

11 

04139 

04532 

04921 

05307 

05690 

06069 

06445 

06818 

07188 

07554 

379 

12 

07918 

08278 

08636 

08990 

09342 

09691 

10037 

10380 

10721  i  11059 

349, 

13 

11394 

11727 

12057 

12385 

12710 

13033 

13353 

13672 

13987 

14301 

323  1 

14 

14613 

14921 

15228 

15533 

15836 

16136 

16435 

16731 

17026 

17318 

300 

15 

1760!) 

17897 

18184 

18469 

18752 

19033 

19312 

19590 

19865 

20139 

281 

16 

20412 

20682 

20951 

21218 

21484 

21748 

22010 

22271 

22  5  SO 

22788 

264 

17 

23045 

23299 

23552 

23804 

24054 

24303 

24551 

24797 

25042 

25285 

249 

18 

25527 

25767 

26007 

26245 

26481 

26717 

26951 

27184 

27415 

27646 

236 

19 

27875 

28103 

28330 

28555 

28780 

29003 

29225 

29446 

29666 

29885 

223 

20 

30103 

30319 

30535 

30749 

30963 

31175 

31386 

31597 

31806 

32014 

212 

21 

32222 

32428 

32633 

32838 

33041 

33243 

33445 

33646 

33845 

34044 

202 

22 

34242 

34439 

34635 

34830 

35024 

35218 

35410 

35602 

35793 

35983 

194 

23 

36173 

36361 

36548 

36735 

36921 

37106 

37291 

37474 

37657 

37839 

185 

24 

38021 

38201 

38381 

38560 

38739 

38916 

39093 

39269 

39445 

39619 

177 

25 

39794 

39967 

40140 

40312 

40483 

40654 

40824 

40993 

41162 

41330 

171 

26 

41497 

41664 

41830 

41995 

42160 

42324 

42488 

42651 

42813 

42975 

164 

27 

43436 

43296 

43456 

43616 

43775' 

43933 

44090 

44248 

44404 

44560 

158 

28 

44716 

44870 

45024 

45178 

45331 

45484 

45636 

45788 

45939 

46089 

153 

29 

46240 

46389 

46538 

46686 

46834 

46982 

47129 

47275 

47421 

47567 

148 

30 

47712 

47856 

48000 

48144 

48287 

48430 

48572 

48713 

48855 

48995 

143 

31 

49136 

49276 

49415 

49554 

49693 

49831 

49968 

50105 

50242 

50379 

138 

32 

50515 

50650 

50785 

50920 

51054 

51188 

51321 

51454 

51587 

51719 

134 

33 

51851 

51982 

52113 

52244 

52374 

52504 

52633 

52763 

52891 

53020  130 

34 

53148 

53275 

53102 

53529 

53655 

53781 

53907 

54033 

54157 

542821126 

35 

54407 

54530 

54654 

54777 

54900 

55022 

55145 

55266 

55388 

55509 

122 

36 

55630 

55750 

55870 

55990 

56410 

56229 

56348 

56m 

56584 

56702 

119 

37 

56820 

56937 

57054 

57170 

57287 

57403 

57518 

57634  57749 

57863 

116 

38 

57978 

58002 

58206 

58319 

58433 

58546 

58658 

58771 

5888S 

58995 

113 

39 

59106 

59217 

59328 

59439 

59549 

59659 

59769 

59879 

59988 

60097 

110 

40 

60206 

60314 

60422 

60530 

60638 

60745 

60852 

60959 

61066 

61172 

107 

41 

61278 

61384 

61489 

61595 

61700 

61804 

61909 

62013 

62117 

62221 

104 

42 

62325 

62428 

62531 

62634 

62736 

62838 

62941 

63042 

63144 

63245 

102! 

43 

63347 

63447 

63548 

63648 

63749 

63848 

63948 

64048 

64147 

64246 

99 

44 

64345 

64443 

64542 

64640 

64738 

64836 

64933 

65030 

65127 

65224 

98 

45 

65321 

65417 

65513 

65609 

65075 

65801 

65896 

65991 

66086 

66181 

96 

46 

(y()276 

66370 

66464 

66558 

66651 

66745 

66838 

66931 

67024 

67117 

94 

47 

67210 

67302 

67394 

67486 

67577 

67669 

67760 

67851 

67942 

68033 

92 

48 

68124 

68214 

68304 

68394 

68484 

68574 

68663 

68752 

68842 

68930 

90 

49 

69020 

69108 

69196 

69284 

69372 

69460 

69548 

69635 

69722 

69810 

88 

50 

69897 

69983 

70070 

70156 

70243 

70329 

70415 

70500 

70586 

70671 

86 

51 

70757 

70842 

70927 

71011 

71096 

71180 

71265 

71349 

71433 

71516 

84 

52 

71600 

71683 

71767 

71850 

71933 

72015 

72098 

72181 

72263 

72345 

82 

53 

72428 

72509 

72591 

72672 

72754 

72835 

72916 

72997 

73078 

73158 

81 

54 

73239 

73319 

73399 

73480 

73559 

73639 

73719 

73798 

73878 

73957 

80 

55 

74036 

74115 

74193 

74272 

74351 

74429 

74507 

74585 

74663 

74741 

78 

*  Each  logarithm  is  supposed  to  have  the  decimal  sign  (•)  before  it. 


556  THE   ENGINEER'S  HANDY-BOOK, 


TABL:E  — {Continued,) 


No. 

0 

1 

2 

3 

4 

5 

6 

7 

H 

9 

d, 
o 

u 
Ph 

56 

74818 

74896 

74973 

75050 

75127 

75204 

75281 

75358 

75434 

75511 

77 

57 

75587 

75663 

75739 

75815 

75891 

75966 

76042 

76117 

76192 

76267 

75 

58 

76342 

76417 

76492 

76566 

76641 

76715 

76789 

76863 

76937 

77011 

74 

59 

77085 

77158 

77232 

77305 

77378 

77451 

77524 

77597 

77670 

77742 

73 

60 

77815 

77887 

77959 

78031 

78103 

78175 

78247 

78318 

78390 

78461 

72 

61 

78533 

78604 

78675 

78746 

78816 

78887 

78958 

79028 

79098 

79169 

71 

62 

79239 

79309 

79379 

79448 

79518 

79588 

79657 

79726 

79796 

79865 

70 

63 

79934 

80002 

80071 

80140 

80208 

80277 

80345 

80413 

80482 

80550 

69 

64 

80618 

80685 

80753 

80821 

80888 

80956 

81023 

81090 

81157 

81224 

68 

65 

81291 

81358 

81424 

81491 

81557 

81624 

81690 

81756 

81822 

81888 

67 

66 

81954 

82020 

82805 

82151 

82216 

82282 

82347 

82412 

82477 

82542 

66 

67 

82607 

82672 

82736 

82801 

S2866 

82930 

82994 

83058 

83123 

83187 

65 

68 

83250 

83314 

83378 

83442 

83505 

83569 

83632 

83695 

83758 

83281 

64 

69 

83884 

83947 

84010 

84073 

84136 

84198 

84260 

84323 

84385 

84447 

63 

70 

84509 

84571 

84633 

84695 

84757 

84818 

84880 

84941 

85003 

85064 

62 

71 

85125 

85187 

85248 

85309 

85369 

85430 

85491 

85551 

85612 

85672 

61 

72 

85733 

85793 

85853 

85913 

85973 

86033 

86093 

86153 

86213 

86272 

60 

73 

86332 

86391 

86451 

86510 

86569 

86628 

86687 

86746 

86805 

86864 

59 

74 

86923 

86981 

F7040 

87098 

87157 

87215 

87273 

87332 

87390 

87448 

58 

75 

87506 

87564 

87621 

87679 

87737 

87794 

87852 

87909 

87966 

88024 

57 

76 

88081 

88138 

88195 

88252 

88309 

88366 

88422 

88479 

88536 

88592 

56 

77 

88649 

88705 

88761 

88818 

•88874 

88930 

88986 

89042 

89098 

89153 

56 

78 

89209 

89265 

89320 

89376 

89431 

89487 

89542 

89597 

89652 

89707 

55 

79 

89762 

89817 

89872 

89927 

89982 

90036 

90091 

90145 

90200 

90254 

54 

80 

90309 

90363 

90417 

90471 

90525 

90579 

90633 

90687 

90741 

90794 

54 

81 

90848 

90902 

90955 

91009 

91062 

91115 

91169 

91222 

91275 

91328 

53 

82 

91381 

91434 

91487 

91540 

91592 

91645 

91698 

91750 

91803 

91855 

53 

83 

9190/ 

91960 

92012 

92064 

92116 

92168 

92220 

92272 

92324 

92376 

52 

84 

92427 

92479 

92531 

92582 

92634 

92685 

92737 

92788 

92839 

92890 

51 

85 

92941 

92993 

93044 

93095 

93146 

93196 

93247 

932^8 

93348 

93399 

51 

86 

93449 

93500 

93550 

93601 

93651 

93701 

93751 

93802 

93852 

93902 

50 

87 

93951 

94001 

94051 

94101 

94151 

94200 

94250 

94300 

94349 

94398 

49 

88 

94448 

94497 

94546 

94596 

94645 

94694 

94743 

94792 

94841 

94890 

49 

89 

94939 

94987 

95036 

95085 

95133 

95182 

95230 

95279 

95327 

95376 

48 

90 

95424 

95472 

95520 

95568 

95616 

95664 

95712 

95760 

95808 

95S56 

48 

91 

1 95904 

95951 

95999 

96047 

96094 

96142 

96189 

96236 

96284 

96331 

48 

92 

'  96378 

96426 

96473 

96520 

96507 

96614 

96661 

96708 

96754 

96801 

47 

93 

96848 

96895 

96941 

96988 

97034 

97081 

97127 

97174 

97220 

97266 

47 

y4 

(\'7  0  1  O 

I  9/ ol^ 

97405 

y/4oi 

y/ 4y/ 

y/  o4o 

y/  ooy 

y/ ooo 

y/ oou 

y/  /  ZD 

ah 

40 

95 

97772 

97818 

97863 

97909 

97954 

98000 

98045 

98091 

98136 

98181 

46 

96 

98227 

98272 

98317 

98362 

98407 

98452 

98497 

98542 

98587 

98632 

45 

97 

98721 

98766 

98811 

98855 

98900 

98945 

98989 

99033 

99078 

45 

98 

99122 

99166 

99211 

99255 

99299 

99343 

99387 

99431 

99475 

99519 

44 

99 

99563 

99607 

99657 

99694 

99738 

99782 

99825 

99869 

99913 

99956 

44 

THE   ENGINEER'S   HANDY-BOOK.  557 

TABLE 


OF  HYPERBOLIC  LOGARITHMS. 


Num. 

Log. 

Num. 

Log. 

Num. 

Log. 

Num. 

Log. 

1*01 

•0099 

1^43 

•3576 

1^85 

•6151 

227 

•8197 

1*02 

•0198 

1-44 

•3646 

1^86 

•6205 

2*28 

•8241 

1*03 

•0295 

1*45 

•3715 

1^87 

•6259 

2^29 

•8285 

1*04 

•0392 

1-46 

•3784 

1*88. 

•6312 

230 

•8329 

1*05 

•0487 

1^47 

•3852 

1*89 

•6365 

2*31 

•8372 

1  06 

•0582 

1^48 

•3920 

1*90 

•6418 

2*32 

•8415 

1*07 

•0676 

1^49 

•3987 

1*91 

•6471 

2*33 

•8458 

1*08 

•0769 

1*50 

•4054 

1*92 

•6523 

2*34 

•8501 

1*09 

•0861 

1-51 

•4121 

1*93 

•6575 

2  35 

•8544 

1*10 

•0953 

1*5^ 

•4187 

1^94 

•6626 

2*36 

•8586 

111 

•1043 

1^53 

•4252 

1*95 

•6678 

2*37 

•8628 

112 

•1133 

1^54 

•4317 

1*96 

•6729 

2*38 

•8671 

1*13 

•1222 

1^55 

•4382 

1*97 

•6780 

2*39 

•8712 

1-14 

•1310 

1^56 

•4456 

1^98 

•6830 

2*40 

•8754 

1-15 

•1397 

1^57 

•4510 

1*99 

•6881 

2*41 

•8796 

1-16 

•1484 

1*58 

•4574 

2*00 

•6931 

2*42 

•8837 

1*17 

•1570 

1*59 

•4637 

2*01 

•6981 

2*43 

•8878 

1*18 

•1655 

1^60 

•4700 

2*02 

•7030 

2*44 

•8919 

1*19 

•1739 

1-61 

•4762 

2*03 

•7080 

•8960 

1*20 

•1823 

1-62 

•4824 

2*04 

•7129 

2^46 

1*21 

•1962 

1*63 

•4885 

2*05 

•7178 

^  rti 

1*22 

•1988 

1*64 

•4946 

2*06 

•7227 

2^48 

1*23 

•2070 

1^65 

•5007 

2*07 

•7275  ' 

^•4Q 

^  Tti/ 

'9122 

1*24 

•2151 

1*66 

•5068 

2*08 

•7323 

2*50 

1*25 

•2231 

1^67 

•5128 

2*09 

•7371 

2^51 

•Q902 

1*26 

•2341 

1*68 

•5187 

2*10 

•7419 

2^52 

•Q949 

1*27 

•2390 

1^69 

•5247 

2*11 

•7466 

2^53 

•QOQO 

1*28 

•2468 

1*70 

•5306 

2  12 

•7514 

2'.^4 

1*29 

•2546 

1*71 

•5364 

2*13 

•7561 

2*/>ri 

VO\J\J 

1*30 

•2623 

1*72 

•5423 

Zi  It: 

•7608 

^  0\J 

aim/ 

1*31 

•2700 

1*73 

•5481 

*>•! 

•7654 

£i  Ot 

132 

•2776 

1^74 

•5538 

'7701 

2^58 

•Q477 

1*33 

•2851 

1^75 

•5596 

2-1  7 

•7747 

Oo 

1-34 

•2926 

1-76 

•5653 

2-18 

•7793 

2^60 

•9555 

X  oo 

1  '77 
Lit 

.C7AQ 

0/  uy 

A  ly 

/  ooy 

L  Dl 

yoyo 

1-36 

•3074 

1-78 

•5766 

2*20 

•7884 

2-62 

•9631 

1-37 

•3148 

1^79 

•5822 

2*21 

•7929 

2^63 

•9669 

1-38 

•3220 

1^80 

•5877 

2^22 

•7975 

2^64 

•9707 

1-39 

•3293 

1-81 

•5933 

2*23 

•80-21 

265 

•9745 

1-40 

•3364 

1-82 

•5988 

2*'24 

•8064 

2^66 

•9783 

1-41 

•3435 

1-83 

•6043 

2-25 

•8109  i 

2*67 

•98-20 

1-42 

•3506 

1^84 

•6097 

2*26 

•8153 

2^68 

•9858 

- 

47* 


558         THE  engineer's  handy-book. 


TABLE  —  (Continued.) 


Num. 

Log. 

Num. 

Log. 

Num. 

Log. 

Num. 

Log. 

^  Do 

yoytj 

3*11 

X  iO'xU 

0  00 

1*2612 

0  yo 

X  0/  01 

9*70 

3*12 

1  •!  ^78 

i  iOl  0 

0  Ot: 

1*2641 

0  yu 

1  •^79fi 
X  0  /  ZU 

9«71 

yyuy 

3-13 

1-1410 

0  00 

1*2669 

Q'Q7 

0  y/ 

1  *^787 
X  0/  0 1 

9-79 

1  '000^ 

X  \J\J\J\J 

1*1449 

0  OU 

1*2697 

0  yo 

1 '^81 9 
X  00  xz 

0.70 

JL  vvt:0 

3*15 

1*1474 

00/ 

1*2725 

0  yy 

1  '^8^7 
X  0001 

9.74 
/lit 

0  xu 

i  iOvO 

0  00 

1*2753 

4*00 

rr  UU 

X  oouz 

9*7^ 

1  'Oil 

Oil 

1  '1  5^7 

0  oy 

1  *9781 
X  z/ ox 

4*01 

t:  ux 

1  *^887 
X  000  j 

1  '01  'S9 

0  iO 

X  XtJOO 

0  uu 

1  •980Q 
X  zouy 

4*09 
rt  i/Z 

1  *'^Q1  9 
X  oyxz 

9*77 

1  .01 88 

1  vlOO 

0  i  y 

X  XUVV 

0  ux 

1  '98^7 

X  ZOOl 

4*0^ 

t:  uo 

1  *^Q^7 
X  oooi 

9*78 

1  '0994 

0  ZV/ 

X  xuox 

0  uz 

1*2864 

A' OA 

rt  \J'± 

X  oyuz 

9'7Q 

1  •09^0 

J.  w^jUv 

3*21 

l-lfifi9 
X  xuuz 

0  uo 

1*2892 

Tt  uo 

1-3987 

9*80 

^  Ov 

1  •09Qfi 
1  uzyo 

3-22 

1  '1  fiQ'^ 
X  xuyo 

0  ut 

1*2919 

rr  UU 

1  *401 1 

X  rtUX  X 

1  V/Ot>i 

0  zo 

1*1794 

X  X  <  Z'l 

0  uo 

1  *9Q47 
X  Ziyti 

4*07 

'±  Ul 

X  'lUOU 

9*89 

Q.94 

1  -17,^.^ 

X  J  /  Uc» 

0  uu 

1  •9Q74 
i  zy  1 

t  uo 

1  *40fi0 
X  tuuu 

9*R^ 

Zi  00 

J.  vt;UZ 

^•9fi 

0  Zr(J 

1  '178^ 
X  i  1  ou 

0  Ul 

1  OUUi 

■4:  uy 

X  TiUOO 

z  ot 

1  '04^8 

3*26 

X  XOi  / 

0  uo 

1  '^()9Q 
i  ouzy 

4'1  0 

4:  J  U 

1  -41 OQ 

X  rrXUy 

1  '047^ 
1  \j'±i  0 

3*27 

1  •  1 847 

X  i  Ot:  1 

0  uy 

i  ouou 

4*1  1 

t:  i  i 

1  -41  ^4 

J  t:  1  Ot 

9  8fi 
Zi  ou 

1  •H.'^Ok 

1  \jO\JO 

3*28 

1-1878 
X  i  0 1  0 

^*7n 

0  1  u 

1  *^08.^ 

X  0\J00 

4*1  9 

'±  iZ 

1  •41  ,^8 
X    1 00 

9*k7 

Zi  Of 

3*29 

1  •!  Q08 

X  i  y vo 

^*71 

0  /  X 

1  *^no 

X  oxxu 

4-1  ^ 
t  xo 

1  -41  89 

X  tiOZ 

1  '0^77 

3'30 

1*1  Q^Q 

X  xyoy 

q-79 

1  -^1  ^7 

X  OXOi 

4*14. 

rr  Xrt 

1  *490H 

X  rrZiUU 

Zj  0(7 

1  -Ofil  9 
1  uu-i  z 

3  31 

1  '1  Q^IQ 
X  xyuy 

0.70 
0/0 

l*'^lfi4 

X  OXUt: 

4*1 

rr  XO 

1  *49^1 
X  rtZOX 

9*00 

z  yv/ 

1  '0^47 

0.09 

0  oz 

1  *1  QQQ 

X  xyyy 

0*74 

0    1  TC 

1 -^1 QO 

XOi  yu 

4*1  ft 

'±  XD 

1*49^1.^ 

X  TbZOO 

9'Ql 
z  y  i 

1  'AAQI 
X  UUOl 

0.00 

0  00 

1  '9090 
X  zuzy 

0  4  0 

1*^917 

X  OZi  1 

4*17 

t:  X  1 

1  •497Q 
X  izi  y 

9  Q9 

Z  aZ 

0  ot 

1  *9n'^Q 
X  zvoy 

0  1  u 

1  '^944 

X  OZrlt 

418 

t:  iO 

X  touo 

Zi  yo 

0  00 

1  *9n8Q 
X  zvoy 

q.77 

Oil 

1  -^971 
X  oz  1  X 

4*1  Q 

4:  X  y 

1  *4^97 

X  IOZI 

9«Q4. 

1  u  /  ot 

0  ou 

1 '91 1 Q 

X  zx xy 

^•78 
0/0 

1  •^9Q7 

X  OZ«7  1 

4*90 

rt  ZU 

X  IOOU 

Zi  y^i 

1 '081  ft 

0.07 

0  0 1 

1  91 4Q 

X  ZiXrty 

0  1  y 

1*3323 

4*91 

4:  ZiX 

1  *4^74 

X  rtO  1  t: 

'  9'Qfi 

1  'OS^l 
±  UotJi 

0  00 

1  '9178 
X  zx  1  0 

0  ou 

1*3350 

4*99 

rt  ZZi 

1-4398 

9-Q7 
^  y/ 

1  uooo 

0  oy 

1  '9908 
X  zzuo 

^•81 
0  ox 

1*3376 

4-9Q 

zo 

1.-4421 

Zi  yo 

1  vjyiy 

1  '99^7 

X  ZZO  1 

^•89 
0  oz  ■ 

1*3402 

4*94 

rr  Zt: 

1.4445 

^  yy 

1  uyoz 

0  Tti 

1  •99fi7 

i  ZZO/ 

0  00 

1  *^4*?8 

X  OtcZO 

4*9^ 

Tt  ZO 

1  -44^0 
X  rttuy 

0  uu 

1  uyoD 

Q'49 

0  t:Z 

1  •9*>Qf^ 
1  z.jyo 

^•84 

0  0^ 

X  OrtOrt 

4*9fi 

t:  ZU 

1  "4409 

X  rtrtyZi 

0  Ui 

1  •!  m  Q 

i  luiy 

i  ZoZO 

0  00 

X  OIOU 

4*97 

X  rtOXU 

0  uz 

i  lUOZ 

Q'44 

X  ZOO'i 

0  00 

X  oouu 

4*98 
t  zo 

X  rtooy 

0  uo 

1  •9*^87 
X  zoo/ 

^•87 
0  0/ 

X  oooz 

4*9Q 

rt  Ziy 

1*4562 

3-04 

1-1118 

3-46 

1-2412 

3-88 

1*3558 

4*30 

1*4586 

3*05 

1*1151 

3*47 

1-2441 

3'89 

1*3584 

4-^1 

1*4609 

3-06 

1-1184 

3-48 

1-2470 

3-90 

1*3609 

4-32 

1*4632 

3-07 

1-1216 

3-49 

1-2499 

3-91 

1*3635 

4-33 

1-4655 

3-08 

1-1249 

3-50 

1-2527 

3-92 

1*3660 

4-34 

1-4678 

3-09 

1-1281 

3-51 

1-2556 

3-93 

1*3686 

4-35 

1-4701 

310 

1-1314 

3-52 

1-2584 

3-94 

1*3711 

4-36 

1-4724 

THE   engineer's   HANDY-BOOK.  559 


TABLE  —  ( Concluded. ) 


Num. 

Log. 

Num. 

Log. 

Num. 

Log. 

Num. 

Log. 

4-S7 

1*4747 

4-79 

1*5665 

5*21 

1-6505 

5*63 

1*7281 

4*38 

1-4778 

4-80 

1*5686 

5-22 

1*6524 

5*64 

1*7298 

4*39 

1-4793 

4-81 

1*5706 

5-23 

1*6544 

5-65 

1-7316 

4*40 

1-4816 

4-82 

1*5727 

5-24 

1*6563 

5-66 

1-7334 

4-41 

1-4838 

4-83 

1*5748 

5-25 

1-6582 

5-67 

1-7351 

4*42 

1-4858 

4-84 

1  5769 

526 

1*6601 

5-68 

1-7369 

4*43 

14883 

4-85 

1*5789 

5-27 

1-6620 

5-69 

1*7387 

4*44 

1-4906 

4-86 

1*5810 

5-28 

1-6639 

570 

1*7404 

4*45 

1-4929 

4-87 

1*5830 

5-29 

1*6658 

5-71 

1*7422 

4*46 

1-4954 

4-88 

1*5851 

5-30 

1*6677 

5-72 

1*7439 

4*47 

1-4973 

4-89 

1-5870 

5-31 

1*6695 

5*73 

1*7457 

4*48 

1-4996 

4-90 

1-5892 

5-32 

1*6714 

5-74 

1-7474 

4-49 

1-5018 

4-91 

1-5912 

5-33 

1*6733 

5-75 

1-7491 

4*50 

i  5040 

4-92 

1*5933 

5-34 

1-6752 

5-76 

1-7509 

4*01 

r5062 

4-93 

1*5953 

5-35 

1-6770 

5-77 

1-7526 

4*52 

1*5085 

4-94 

1-5973 

536 

l-67c9 

5-78 

1-7544 

4'53 

1-5107 

4-95 

1-5993 

5-37  ' 

1-6808 

5-79 

1-7561 

4*54 

1-5129 

4-96 

1-6014 

5-38 

1-6826 

5-80 

1-7578 

4-55 

1-5151 

4'97 

1-6034 

5-39 

1-6845 

5-8I 

1-7595 

1-5173 

4-98 

1*6054 

5-40 

1*6863 

5-82 

1-7613 

4*57 

1-5195 

4-99 

1-6074 

5-41 

1*6882 

5-83 

1-7630 

4*58 

1-5216 

500 

1*6094 

5-42 

1-6900 

5-84 

1-7647 

4*59 

1-5238 

501 

1*6114 

5-43 

1-6919 

5-85 

1-7664 

4*60 

1-5260 

502 

1-6134 

5-44 

1-6937 

5-86 

1-7681 

4*61 

1-5282 

5-03 

1-6154 

5*45 

1-6956 

5-86 

1-7698 

4*62 

1-5303 

504 

1-6174 

5*46 

1*6974 

5-87 

1*7715 

4  63 

1-5325 

505 

1*6193 

5-47 

1*6992 

5-88 

1*7732 

4*64 

1-5347 

5-06 

1-6213 

5-48 

1*7011 

5-89 

1-7749 

4*65 

1-5368 

5-07 

1*6233 

5-49 

1-7029 

5-90 

1-7766 

4*66 

1-5390 

5-08 

1*6253 

5-50 

1-7047 

5-91 

1-7783 

4-67 

1-5411 

5-09 

1-6272 

5*51 

1*7065 

5-92 

1-7800 

4-68 

1*5432 

5-10 

1-6292 

5*52 

1*7083 

5-93 

1-7817 

4*69 

1*5454 

5-11 

1-6311 

5*53 

1*7101 

5-94 

1-7833 

4*70 

1*5475 

512 

1-6331 

5*54 

1*7119 

5-95 

1-7850 

4-71 

1*5496 

513 

1-6351 

5-55 

1-7137 

5-96 

1-7867 

4-72 

1*5518 

5-14 

1-6370 

5*56 

1*7155 

5-97 

1-7884 

4-73 

1-5539 

5-15 

1-6389 

5*57 

1*7173 

5-99 

1-7900 

4-74 

1-5560 

5-16 

1-6409 

5-58 

1*7191 

6-00 

1*7917 

4-75 

1-5581 

5-17 

1-6428 

5*59 

1*7209 

6-01 

1-7934 

4-76 

1*5602 

5-18 

1-6448 

5*60 

1-7227 

6-02 

1-7950 

4-77 

1-5623 

5*19 

1-6463 

5*61 

1*7245 

6*03 

1-7967 

4-78 

1-5644 

1  5-20 

1-6486 

5*62 

1-7263 

6*04 

1-7989 

560  THE  engineer's  hanby-book. 


Peculiarities  of  Multiplication. 

The  multiplication  of  987654321  by  45  gives  4444444445. 
Reversing  the  order  of  the  digits,  and  multiplying  123456789 
by  45,  we  get  a  result  equally  curious,  5555555505.  If  we  take 
123456789  as  the  multiplicand,  and,  interchanging  the  figures  45, 
take  54  as  the  multiplier,  we  obtain  another  remarkable  product, 
6666666606.  Returning  to  the  multiplicand  first  used,  987654321, 
and  taking  54  as  the  multiplier  again,  we  get  53333333334, —  all 
threes  except  the  first  and  last  figures,  which  read  together  54,  the 
multiplier.  Taking  the  same  multiplicand,  and  using  27,  the 
half  of  54,  as  the  multiplier,  we  get  a  product  of  2666666667, — 
all  sixes  except  the  first  and  last  figures,  which  read  together  27, 
the  multiplier.  Next,  interchanging  the  figures  in  the  number 
27,  and  using  72  as  a  multiplier,  with  987654321  as  the  multi- 
plicand, we  obtain  a  product  of  71111111112, —  all  ones  except 
the  first  and  last  figures,  which  read  together  gives  72,  the  mul- 
tiplier. 

Decimal  Arithmetic. 

Decimal  Arithmetic  is  the  most  simple  and  explicit  mode  of 
performing  practical  calculations,  on  account  of  its  doing  away 
with  the  necessity  of  fractional  parts  in  the  fractional  form, 
thereby  reducing  long  and  tedious  operations  to  a  few  figures. 

Decimal  Fractions  are  fractions  in  which  the  denominator  is  a 
unit,  or  1,  with  ciphers  annexed,  in  which  case  they  are  com- 
monly expressed  by  writing  the  numerator  only  with  a  point  be- 
fore it,  by  which  it  is  separated  from  whole  numbers  ;  thus  '5,  which 
denotes  five-tenths,  ;  '25,  that  is,  -f^jj.  Ciphers  on  the  right 
hand  of  decimals  are  of  no  value  whatever ;  but  placed  on  the 
left  hand,  they  diminish  the  decimal  value  in  a  tenfold  propor- 
tion ;  thus  '6  signifies  6  tenths ;  '06  signifies  6  hundredths;  and  '006 
signifies  6  thousandths  of  the  integer  or  whole  number. 


THE   ENGINEER'S   HANDY-BOOK.  561 


TABLE 

OF  VULGAR  AND  DECIMAL  FRACTIONS  OF  AN  INCH. 


Vulgar 
Fractions 
of  an  Inch. 


1 

3^ 
1 

Tg 
1 

1 

i 

3 
1 


1 

32 


1 

3-2 


4 
5 
IS 
5  1 

^2 


Decimal 
Fractions 
ofan  Inch. 


•03125 

•0625 

•09375 

•125 

•15625 

•1875 

•21875 

•25 

•28125 

•3125 

•34375 


Vulgar 
Fractions 
of  an  Incli. 


3 
5 
3 
H 


1 

32 


3  2 


1  1 

2  32 

9  1 

T6  32 

¥ 

5  1 

■g"  32 


Decimal 
Fractions 
ofan  Inch. 


•375 

•40625 

•4375 

•46375 

•5 

•53125 

•5625 

•59375 

•625 

•65625 


Vulgar 
Fractions 
ofan  Inch. 


1  1 

T(T 
I  I 

Tg 

3 

4 

3 

4 
13. 
I  6 
13 
1  6 

7 

8" 

7 


1  5 


1 

32 


1 

32 


1 

32 


1 

32 


Decimal 
Fractions 
ofan  Inch. 


•6875 

•71875 

•75 

•78125 

•8125 

84375 

•875 

•90625 

•9375 

•96875 


TABLE, 


Com- 
mon 
Frac- 
tion. 


32 

1 

1  6 

3 

^2 
1 

5 
32 

3 

7 

^2 
1 


Deci- 
mal. 


•0312 
•0625 
•0937 
•1250 
•1562 
•1875 
•2187 
•2500 


Com- 
mon 
Frac- 
tion. 


9 

32 
5 

1  1 

32 
3 
■g" 
1  3 
32 

U 

1 


Deci- 
mal. 


•2812 
•3125 
•3437 
•3750 
•4062 
•4375 
•4687 
•5000 


Com- 
mon 
Frac- 
tion. 


1  7 

32 
9 

T(7 

1  9 
3  2 

5 
8" 

2  1 


T6 
2  3 
32 

3 

4 


Deci- 
mal. 


•5312 
•5625 
•5977 
•6250 
•6562 
•6875 
•7187 
•7500 


Com- 
mon 
Frac- 
tion. 


33 

a 

il 

I 

29 
32 
1  n 
7^ 
3  1 
32 
32 
32 


Deci- 
mal. 


•7812 
•8125 
•8437 
•8750 
•9062 
•9375 
•9687 
L-000 


2L 


562 


THE   engineer's  HANDY-BOOK. 


Units. 

Unit  of  heat. — The  unit  of  heat  varies:  the  French  unit  of 
heat,  called  a  "  caloric, is  the  amount  of  heat  necessary  to  raise 
one  kilogramme  (2*2046215  pounds)  of  water  one  degree  Centi- 
grade, or  from  0^  C.  to  1°  C.  In  this  country  and  in  England 
the  amount  of  heat  necessary  to  raise  one  pound  of  water  one  de- 
gree Fahrenheit,  or  from  32"^  Fah.  to  33°  Fah.,  is  taken  as  the 
unit  of  heat. 

Fop  calculations  involving  quantity  of  heat,  thermometrical 
temperatures  are  of  no  value  without  a  knoAvledge  of  the  capac- 
ity of  heat  which  any  body  possesses.  The  quantity  of  heat  re- 
quired to  raise  various  bodies  to  any  given  temperature  differs 
considerably.  Water,  as  possessing  the  greatest  "  specific  "  heat 
of  any  known  substance,  has  been  universally  accepted  as  a 
standard,  and  the  unit  for  the  quantity  of  heat  is  that  amount 
which  will  raise  1  pound  of  water  1°  Fah.  from  a  temperature  of 
32°  Fah.  To  be  strictly  accurate,  the  w^ater  should  be  distilled 
and  the  lower  temperature  uniform,  in  any  series  of  experiments, 
for  the  amount  of  heat  to  raise  w^ater  1°  varies  slightly  at  differ- 
ent temperatures. 

Unit  of  length. — The  unit  of  length  used  in  this  country  and 
in  England  is  the  yard,  the  length  of  which  has  been  determined 
by  means  of  a  pendulum  vibrating  seconds,  in  the  latitude  of 
London,  in  a  vacuum  and  at  the  level  of  the  sea.  The  length  of 
such  a  pendulum  is  to  be  divided  into  3,913,929  parts,  and 
3,600,000  of  these  parts  are  to  constitute  a  yard.  The  yard  is 
divided  into  36  inches,  so  that  the  length  of  the  seconds  pendu- 
lum in  London  is  39*13929  inches. 

The  division  of  a  foot  into  12  inches  enables  various  fractional 
parts,  such  as  i,  },  i,  J,  I,  f ,  to  be  made  by  the  use  of  whole 
numbers,  and,  in  this  respect,  it  is  far  more  convenient  than 
having  the  foot  divided  into  ten  parts,  which  will  only  give  I  and 
\  in  the  whole  divisions,  without  the  use  of  decimals  or  fractions. 
So  far  as  the  inch  is  concerned,  it  is  always  divided  into  several 


THE   engineer's  HANDY-BOOK. 


563 


proportions,  including  tenths,  on  any  good  rule,  and  we  use  those 
most  preferred,  so  that  it  possesses  all  the  advantages  of  the  deci- 
mal system  with  others  peculiarly  its  own. 

The  French  unit  of  length,  called  the  metre,  has  been  taken  as 
being  the  ten-millionth  part  of  the  quadrant  of  a  meridian  pass- 
ing through  Paris ;  that  is  to  say,  the  ten-millionth  part  of  the 
distance  between  the  equator  and  the  pole,  measured  through 
Paris.  It  is  equal  to  39*3707898  inches.  The  metre  is  divided 
into  one  thousand  millimetres,  one  hundred  centimetres,  and  ten 
decimetres ;  while  a  decimetre  is  *ten  metres,  a  hectometre  one 
hundred  metres,  a  kilometre  one  thousand  metres,  and  a  myria- 
metre  ten  thousand  metres. 

One  English  yard  is  equal  to  0*91438  m^tre;  while  one  mile  is 
equal  to  1*60931  kilometres. 

Unit  of  surface.  —  For  the  unit  of  surface,  the  square  inch, 
foot,  and  yard  adopted  in  this  country  and  in  England  are  re- 
placed in  the  metric  system  by  the  square  millimetre,  centimetre, 
decimetre,  and  metre. 

The  unit  of  length  squared  becomes  the  unit  for  surface  area, 
and  the  same  length  cubed  is  the  unit  for  capacity.  Cubic  inches 
are  generally  used  to  express  volumes  of  water,  while  cubic  feet 
is  a  convenient  expression  for  steam. 

Unit  of  capacity. — The  cubic  inch,  foot,  and  yard  furnish 
measures  of  capacity  ;  but  irregular  measures,  such  as  the  pint 
and  gallon,  are  also  used  in  this  country  and  in  England.  The 
yallon  contains  t^n  pounds  avoirdupois  weight  of  distilled  water 
ato;2  Fah. ;  the  pint  is  one-eighth  part  of  a  gallon. 
*  The  French  unit  of  capacity  is  the  cubic  decimetre  or  litre, 
equal  to  1*7607  English  pints,  or  0*2200  English  gallon  ;  and  we 
have  cubic  inches,  decimetres,  centimetres,  and  millimetres. 

Unit  of  weight. — The  unit  of  weight  used  in  this  country  and 
in  England,  viz.,  the  pound,  is  derived  from  the  standard  gallon, 
which  contains  277*274  cubic  inches ;  the  weight  of  one-tenth  of 
this  is  the  pound  avoirdupois,  which  is  divided  into  7000  grains. 

The  French  measures  of  weight  are  derived  at  once  from  the 


564  THE   ENGINEER'S  HANDY-BOOK, 

measures  of  capacity,  by  taking  the  weight  of  cubic  millimetres, 
centimetres,  decimetres,  or  metres  of  water  at  their  maximum 
density,  that  is,  at  4°  C.  or  39°  Fah. 

Unit  of  time  or  duration. — The  unit  of  time  or  duration  is  the 
same  for  all  civilized  countries.  The  twenty-fourth  part  of  a  mean 
solar  day  is  called  an  hour,  which  contains  sixty  minutes,  which 
again  is  divided  into  sixty  seconds.  The  second  is  universally 
used  as  the  unit  of  duration. 

Another  unit  of  time  is  the  period  occupied  by  the  earth  in 
making  one  revolution  around*the  sun,  in  reference  to  an  assumed 
•fixed  star,  which  unit  is  called  a  sidereal  year,  and  contains  365 
days,  6  hours,  9  minutes,  9'6  seconds  mean  solar  time. 

Unit  of  velocity.  —  The  units  of  velocity  adopted  by  different 
scientific  writers  vary  somewhat ;  the  most  usual,  perhaps,  in  re- 
gard to  sound,  falling  bodies,  projectiles,  etc.,  is  the  velocity  of  feet 
or  metres  per  second.  In  the  case  of  light  and  electricity,  miles 
and  kilometres  per  second  are  employed. 

Unit  of  work.  —  In  this  country  and  in  England,  the  unit  of 
work  is  usually  the  foot-pound,  viz.,  the  force  necessary  to  raise 
one  pound  weight  one  foot  above  the  earth  in  opposition  to  the 
force  of  gravity.  A  horse-power  is  equal  to  33,000  pounds  raised 
to  a  height  of  one  foot  in  one  minute  of  time. 

In  France  the  kilogrammetre  is  the  unit  of  work,  and  is  the  force 
necessary  to  raise  one  kilogramme  to  a  height  of  one  metre  against 
the  force  of  gravity.  One  kilogrammetre  =  7*233  foot-pounds. 
The  cheval-pouvoir  is  nearly  equal  to  the  English  horse-power,  and 
is  equivalent  to  32,500  pounds  raised  to  a  height  of  one  foot  in 
one  minute  of  time.  The  force  competent  to  produce  a  velocity* 
of  one  metre  in  one  second,  in  a  mass  of  one  gramme,  is  some- 
times adopted  as  a  unit  of  force. 

Unit  of  pressure. — The  pressure  of  the  atmosphere  at  the  level 
of  the  ocean,  with  the  barometer  at  30  inches,  is  taken  as  the  unit 
in  estimating  and  comparing  pressures  and  elastic  forces. 


THE   ENGINEER'S  HANDY-BOOK. 


565 


TABLE 


SHOWING  ALL   THE   UNITS  OF  LENGTH  RECOGNIZED  IN  ENGLAND  SINCE 
THE  SIXTEENTH  CENTURY. 

3  barleycorDS       .       .       .       .       .1  inch. 

1*2  inches  1  Surveyor's  foot  tenth. 

1-875  foot  tenths  (2*25  inches)      .       .    1  nail. 
1*777  nails  (4  inches)    ....    1  hand. 

(6'1538  inches  side  of  cube  of  wine  gal.  of  223  cub.  in.) 
(6-5576     "       "    "      "    "  beer  gal.  of  282  cub.  in.) 


1-98  hands  (7*92  inches) 
ri36  links  (9  inches) 
1*333  quarters  (12  inches) 

(12*907  inches  side  of  cubic  bush,  or 
1*875  feet  (2*5  quarters) 
1*2  ell  Hamburg  (3  quarters) 
1*33  ell  Flemish  (3  feet) 

(38*73  inches  side  of  cubic  wine 
1*25  yards  (5  quarters) 
1*644  ell  English  (6  quarters) 

(5*0397  feet  side  of  cubic  cord  or  128 
1*333  ell  French  (6  feet) 
2*75  fathoms  (5*5  yards) 
4  rods  (22  yards) 

(68*57  yards  side  of  square  acre, 
10  chains 

8  furlongs  .  . 
1*158  statute  miles 
2*59  geographical  miles  (3  statute  miles) 

A  cubit  is  two  feet. 

A  great  cubit  is  eleven  feet. 

A  palm  is  three  inches. 

A  span  is  ten  and  seven-eighth  inches. 

A  pace  is  three  feet. 

A  barrel  of  flour  weighs  196  pounds. 

A  barrel  of  pork  weighs  200  pounds. 
48 


1  link. 
1  quarter. 
1  foot. 
2150-42  cub.  in.) 
1  ell  Hamburg. 
1  ell  Flemish. 
1  yard, 
ton  of  58212  cub.  in.) 
1  ell  English. 
1  ell  French, 
cubic  feet.) 
1  fathom. 

1  rod,  pole  or  perch. 
1  chain. 


1  furlong. 

1  statute  mile. 

1  geographical  mile, 

1  league. 


566 


THE   ENGINEER'S  HANDY-BOOK. 


A  barrel  of  powder  weighs  twenty-five  pounds. 

A  firkin  of  butter  weighs  fifty-six  pounds.  ; 

A  tub  of  butter  weighs  eighty-four  pounds. 

Atoms  and  Molecules. 

The  term  atom  has  been  exclusively  appropriated  by  the 
chemist,  while  the  mathematician  and  physicist  have  preferred  to 
adopt  the  word  molecule  to  signify  those  ultimate  constituents  of 
matter  upon  whose  motions  and  relations  depend  the  various  states 
of  all  bodies  solid,  liquid,  and  gaseous.  It  is  said  that  atoms  are 
attracted  to  each  other  by  the  attraction  of  cohesion,  and  repelled 
by  the  force  of  repulsion.  By  the  action  of  both  these  forces,  the 
atoms  are  kept  in  a  state  of  rest.  The  solidity  of  a  solid  depends 
upon  the  fact  that  each  pair  of  atoms  is  in  this  state  of  equilib- 
rium. These  atoms  are  supposed  to  be  of  an  oblate,  spheroidal 
form. 

The  word  particle  is  also  freely  made  use'of  as  involving  no 
hypothesis,  and  meaning  simply  a  small  part  of  any  body.  Mole- 
cule has  been  defined  by  Maxwell  as  "the  smallest  possible  portion 
of  a  particular  substance ; "  and,  again,  as  "  that  small  portion  of 
the  substance  which  moves  as  one  lump  in  the  motion  of  agita- 
tion." 

Every  substance  is  now  supposed  to  be  composed  of  an  im- 
mense number  of  molecules,  which,  even  in  the  solid  state,  are 
never  entirely  at  rest,  and  in  the  gaseous  are  in  a  state  of  per- 
petual violent  commotion,  rushing  about  in  straight  lines  in  all 
directions  with  inconceivable  rapidity. 

The  difficulty  of  proving  or  disproving  the  molecular  theory 
lies  in  our  inability  to  determine  the  size  or  shape  of  a  molecule 
by  any  means  in  our  power.  The  most  powerful  microscope  fails 
utterly  to  show  them,  and  should  some  material  for  lenses  be  dis- 
covered infinitely  superior  to  glass  or  other  material  at  present  in 
use,  we  should  fall  far  short  of  appreciating  a  molecule  through 
the  vision. 


THE   engineer's  ilANDY-BOOK. 


567 


TABLE 

OF   SQUARES,    CUBES,    AND   SQUARE   AND    CUBE   ROOTS    OF  ALL 
NUMBERS  FROM  1  TO  620. 


Number. 

Square. 

Cube. 

Square  Root. 

Cube  Root. 

1 

1 

1 

1.  . 

1. 

2 

4 

8 

1.4142 

136 

1.2599 

21 

3 

9 

27 

1.7230 

508 

1.4422 

496 

4 

16 

64 

2. 

1.5874 

Oil 

5 

25 

125 

2.2360 

68 

1.7099 

759 

6 

36 

216 

2.4494 

897 

1.8171 

206 

7 

49 

343 

2.6457 

513 

1.9129 

312 

8 

64 

512 

2.8284 

271 

2. 

9 

81 

729 

3. 

2  0800 

837 

10 

1 

00 

1  000 

3.1622 

777 

2.1544 

347 

11 

1 

21 

1  331 

3.3166 

248 

2.2239 

801 

12 

1 

44 

1  728 

3.4641 

016 

2.2894 

286 

13 

1 

69 

2  197 

3  605/) 

513 

2.3513 

347 

14 

1 

96 

2  744 

3.7416 

574 

2.4101 

422 

15 

2 

25 

3  375 

3.8729 

833 

2.4662 

121 

16 

2 

56 

4  096 

4* 

2.5198 

421 

17 

2 

89 

4  913 

4.1231 

056 

2.5712 

816 

18 

3 

24  = 

5  832 

4.2426 

407 

2.6207 

414 

19 

3 

61 

6  859 

4.3585 

989 

2.6684 

016 

20 

4 

00 

8  000 

4.4721 

36 

2.7144 

177 

21 

4 

41 

9  261 

4.5825 

2.7589 

243 

22 

4 

84 

10  648 

4.6904 

158 

2.8020 

393 

23 

5 

29 

12  167 

4.7958 

315 

2.8438 

67 

24 

5 

76 

13  824 

4.8989 

795 

2^8844 

991 

25 

6 

25 

15  625 

5. 

2.9240 

177 

26 

6 

76 

17  576 

195 

2.9224 

96 

27 

7 

29 

19  683 

5.1961 

524 

3. 

28 

7 

84 

21  952 

5.2915 

026 

889 

29 

8 

41 

24  389 

5.3851 

648 

1  uo 

30 

9 

00 

27  000 

5.4772 

256 

Q  1079 

325 

31 

9 

61 

29  791 

5*.5677 

644 

3.1413 

806 

32 

10 

24 

32  768 

5  6568 

542 

3.1748 

021 

33 

10 

89 

35  937 

5.7445 

626 

3!2075 

343 

34 

11 

56 

39  304 

5.8309 

519 

3.2396 

118 

35 

12 

25 

42  875 

5.9160 

798 

3.2710 

663 

36 

12 

96 

46  656 

6. 

3.3019 

272 

37 

13 

69 

50  653 

6.0827 

625 

3.3322 

218 

38 

14 

44 

54  872 

6.1644 

14 

3.3619 

754 

39 

15 

21 

59  319 

6.2449 

98 

3.3912 

114 

40 

16 

00 

64  000 

(>.3245 

553 

3.4199 

519 

41 

16 

81 

68  921 

6.4031 

242 

3.4482 

172 

THE    ENGINEER'S  HANDY-BOOK. 
TABLE  —  (Continued) 


OP  SQUARES,  CUBES,  AND  SQUARE  AND  CUBE  ROOTS,  ETC. 


liumDGr. 

Square. 

Cube. 

Square  Root. 

Cube  Root. 

42 

17  64 

74  088 

6.4807  407 

3.4760  266 

43 

18  49 

79  507 

6.5574  385 

3,5033  931 

44 

19  36 

85  184 

6.6332  496 

3.5303  483 

45 

20  25 

91  125 

6.7082  039 

3.5568  933 

46 

21  16 

97  336 

6.7823  3 

3.5830  479 

47 

22  09 

103  823 

6.8556  546 

3.6088  261 

48 

23  04 

110  592 

6.9282  032 

3.6342  411 

49 

24  01 

117  649 

7. 

3.6593  057 

60 

25  00 

125  000 

7.0710  678 

3.6840  314 

51 

26  01 

132  651 

7.1414  284 

3.7084  298 

52 

27  04 

140  608 

7.2111  026 

3.7325  111 

53 

28  09 

148  877 

7.2801  099 

3.7562  858 

54 

29  16 

157  464 

7.3484  692 

3.7797  631 

55 

30  25 

166  375 

7.4161  985 

3.8029  525 

56 

31  36 

175  616 

7.4833  148 

3.8258  624 

57 

32  49 

185  193 

7.5498  344 

3.8485  Oil 

58 

33  64 

195  112 

7.6157  731 

3.8708  766 

59 

34  81 

205  379 

7.6811  457 

3.8929  965 

60 

36  00 

216  000 

7.7459  667 

3.9148  676 

61 

37  21 

226  981 

7.8102  497 

3.9364  972 

62 

38  44 

238  328 

7.8740  079 

3.9578  915 

63 

39  69 

250  047 

7.9372  539 

3.9790  571 

64 

40  96 

262  144 

8. 

4. 

65 

42  25 

274  625 

8.0622  577 

4.0207  256 

66 

43  56 

287  496 

8.1240  384 

4.0412  401 

67 

44  89 

300  763 

8.1853  528 

4.0615  48 

68 

46  24 

314  432 

8.2462  113 

4.0816  551 

69 

47  61 

328  509 

8.3066  239 

4.1015  661 

70 

49  00 

343  000 

8.3666  003 

4.1212  853 

71 

50  41 

357  911 

8.4261  498 

4.1408  178 

72 

51  84 

373  248 

8.4852  814 

4.1601  676 

73 

53  29 

389  017 

8.5440  037 

4.1793  39 

74  • 

54  76 

405  224 

8.6023  253 

4.1983  364 

75 

56  25 

421  875 

8.6602  54 

4.2171  633 

76 

57  76 

438  976 

8.7177  979 

4.2358  236 

77 

59  29 

456  533 

8.7749  644 

4.2543  21 

78 

60  84 

474  552 

8.8317  609 

4.2726  586 

79 

62  41 

493  039 

8.8881  944 

4.2908  404 

80 

64  00 

512  000 

8.9442  719 

4.3088  695 

81 

65  61 

531  441 

9. 

4.3267  487 

82 

67  24 

551  368 

9.0553  851 

4.3444  815 

83 

68  89 

571  787 

9.1104  336 

4.3620  707 

THE   ENGINEER'S    HANDY-BOOK.  5 

T  A  B  L  E  —  ( Continued) 


OF  SQUARES,  CUBES,  AND  SQUARE  AND  CUBE  ROOTS,  ETC. 


Number. 

Square. 

Cube. 

Square  Root. 

Cube  Root. 

84 

70  56 

592  704 

9.1651 

514 

4.3795 

191 

85 

72  25 

614  125 

9.2195 

445 

4.3968 

296 

86 

73  96 

636  056 

9.2736 

185 

4.4140 

049 

87 

75  69 

658  503 

9.3273 

791 

4.4310 

476 

88 

77  44 

681  472 

9.3808 

315 

4.4479 

602 

89 

79  21 

704  969 

9.4339 

811 

4.4647 

451 

90 

81  00 

729  000 

9.4868 

33 

4.4814 

047* 

91 

82  81 

753  571  • 

9.5393 

92 

4.4979 

414 

92 

84  64 

778  688 

9.5916 

03 

4.5143 

574 

93 

86  49 

804  357 

9.6436 

508 

4.5306 

549 

94 

88  36 

830  584 

9.6953 

597 

4.5468 

359 

95 

90  25 

857  375 

9.7467 

943 

4.5629 

026 

96 

92  16 

884  736 

9.7979 

59 

4.5788 

57 

97 

94  09 

912  673 

9.8488 

578 

4.5947 

009 

98 

96  04 

941  192 

9.8994 

949 

4.6104 

363 

99 

98  01 

970  299 

9.9498 

744 

4.6260 

65  1 

100 

1 

00  00 

1 

000  000 

10. 

4.6415 

888 

101 

1 

02  01 

1 

030  301 

10.0498 

756 

4.6570 

095 

102 

1 

04  04 

1 

061  208 

10.0995 

049 

4.6723 

287 

103 

1 

06  09 

1 

092  727 

10.1488 

916 

4.6875 

482 

104 

1 

08  16 

1 

124  864 

10.1980 

89 

4.7026 

694 

105 

1 

10  25 

1 

157  625 

10.2469 

508 

4.7176 

94 

106 

1 

12  36 

1 

191  016 

10.2956 

301 

4.7326 

235 

107 

1 

14  49 

1 

225  043 

10.3440 

804 

4.7474 

594 

108 

1 

16  64 

1 

259  712 

10.3923 

048 

4.7622 

032 

109 

1 

18  81 

1 

295  029 

10.4403 

065 

4.7768 

562 

110 

1 

21  00 

1 

331  000 

10.4880 

885 

4.7914 

199 

111 

1 

23  21 

1 

367  631 

10.5356 

538 

4.8058 

995 

112 

1 

25  44 

1 

404  92^ 

10.5830 

052 

4.8202 

845 

113 

1 

27  69 

1 

442  897 

10.6301 

458 

4.8345 

881 

114 

1 

29  96 

1 

481  544 

10.6770 

783 

4.8488 

076 

115 

1 

32  25 

1 

520  875 

10.7238 

053 

4.8629 

442 

116 

1 

34  56 

1 

560  896 

10.7703 

296 

4.8769 

99 

117 

1 

36  89 

1 

601  613 

10.8166 

538 

4.8909 

732 

118 

1 

39  24 

1 

643  032 

10.8627 

805 

4.9048 

681 

119 

1 

41  61 

1 

685  159 

10.9087 

121 

4.9186 

847 

120 

1 

44  00 

1 

728  000 

10.9544 

512 

4.9324 

242 

121 

1 

46  41 

1 

771  561 

11. 

4.9460 

874 

122 

1 

48  34 

1 

815  848 

11.0453 

61 

4.9596 

757 

123 

1 

51  29 

1 

860  867 

11.0905 

365 

4.9731 

898 

124 

1 

53  76 

1 

906  624 

11.1355 

287 

4.9866 

31 

125 

1 

56  25 

1 

953  125 

11.1803 

399 

5. 

48* 


570  THE  engineer's  handy-book. 

T  A  B  L  E  —  ( Continued) 


OP  SQUARES,  CUBES,  AND  SQUARE  AND  CUBE  ROOTS,  ETC. 


Number. 

Square. 

Cube. 

Square  Root. 

Cube  Root. 

126 

1 

58 

76 

2 

000 

376 

11.2249 

722 

5.0132  979 

127 

1 

61 

29 

2 

048 

383 

11.2694 

277 

5.0265  257 

128 

1 

63 

84 

2 

097 

152 

11.3137 

085 

5.0396  842 

129 

1 

66 

41 

2 

146 

689 

11.3578 

167 

5.0527  743 

130 

1 

69 

00 

2 

197 

000 

11.4017 

543 

5.0657  97 

131 

1 

71 

61 

2 

248 

091 

11.4455 

231 

5.0787  531 

132 

1 

74 

24 

2 

299 

968 

11.4891 

253 

5.0916  434 

133 

1 

76 

89 

2 

352 

63f 

11.5325 

626 

5.1044  687 

134 

1 

79 

56 

2 

406 

104 

11.5758 

369 

5.1172  299 

135 

1 

82 

25 

2 

460 

375 

11.6189 

5 

5.1299  278 

136 

1 

84 

96 

2 

515 

456 

11.6619 

038 

5.1425  632 

137 

1 

87" 

69 

2 

571 

353 

11.7046 

999 

5.1551  367 

138 

1 

90 

44 

2 

628 

072 

11.7473 

401 

5.1676  493 

139 

] 

93 

21 

2 

685 

619 

11.7898 

261 

5.1801  015 

140 

1 

96 

00 

2 

744 

000 

11.8321 

596 

5.1924  941 

141 

I 

98 

81 

2 

803 

221 

11.8743 

421 

5.2048  279 

142 

2 

01 

64 

2 

863 

288 

11.9163 

753 

5.2171  034 

143 

2 

04 

49 

2 

924 

207 

11.9582 

607 

5.2293  215 

144 

2 

07 

36 

2 

985 

984 

12. 

5.2414  828 

145 

2 

10 

25 

3 

048 

625 

12.0415 

946 

5.2535  879 

146 

2 

13 

16 

3 

112 

136 

12.0830 

46 

5.2656  374 

147 

2 

16 

09 

3 

176 

523 

12.1243 

557 

5.2776  321 

148 

2 

19 

04 

3 

241 

792 

12.1655 

251 

5.2895  725 

149 

2 

22 

01 

3 

307 

949 

12.2065 

556 

5.3014  592 

150 

2 

25 

00 

3 

375 

000 

12.2474 

487 

5.3132  928 

151 

2 

28 

01 

3 

442 

951 

12.2882 

057 

5.3250  74 

152 

2 

31 

04 

3 

511 

008 

12.3288 

28 

5.3368  033 

153 

2 

34 

09 

3 

581 

577 

12.3693 

169 

5.3484  812 

154 

2 

37 

16 

3 

652 

264 

1 2  40Q6 

736 

5.3601  084 

155 

2 

40 

25 

3 

723 

875 

12.4498 

996 

5.3716  854 

156 

2 

43 

36 

3 

796 

416 

1 2  4HQQ 

96 

5.3832  126 

157 

2 

46 

49 

3 

869 

893 

J.  ^d,KJ  idO  U 

641 

5.3946  907 

158 

2 

49 

64 

3 

944 

312 

12.5698 

051 

5.4061  202 

159 

2 

52 

81 

4 

019 

679 

12.6095 

202 

5.4175  015 

160 

2 

56 

00 

4 

096 

000 

12.6491 

106 

5.4288  352 

161 

2 

59 

21 

4 

173 

281 

12.6885 

775 

5.4401  218 

162 

2 

62 

44 

4 

251 

528 

12.7279 

221 

5.4513  618 

163 

2 

65 

69 

4 

330 

747 

12.7671 

453 

5.4625  556 

164 

2 

68 

96 

4 

410 

944 

12.8062 

485 

5.4737  037 

165 

2 

72 

25 

4 

492 

125 

12.8452 

326 

5.4848  066 

166 

2 

75 

56 

4 

574 

296 

12.8840 

987 

5.4958  647 

167 

2 

78 

89 

4 

657 

463 

12.9228 

48 

5.5068  784 

THE   ENGINEER'S  HANDY-BOOK. 


571 


T  A  B  L  E  —  ( Cmtinued) 


OF  SQUARES,  CUBES,  AND  SQUARE  AND  CUBE  ROOTS,  ETC. 


Numbei*. 

Square. 

Cube. 

Square  Root. 

Cube  Root. 

168 

o 

oo 
oA 

0/1 

A    T  /1 1 

4  /41 

ooZ 

1  O  OA1  A 

iz.yDi4 

Qt  A 

oi4 

X  XI  7Q 
O.Oi  /O 

AQA 

4o4 

169 

o 

O 

OD 

oi 

A  QO/J 

4  oZo 

QAO 

ouy 

1  o 

io. 

X  XOQ7 

o.oZo/ 

7/1  Q 

/  4o 

170 

Z 

QO 

oy 

AA 

A    OI  Q 

4  yio 

AAA 

UUU 

1  O  AOQ /I 

io.Uoo4 

A/1  Q 

U4o 

X  XO(»A 

o.ooyo 

XQO 

Ooo 

171 

/I  1 

41 

AAA 
0  UUU 

OI  1 

Zi  i 

io.U/oo 

yoo 

X  XX/\/1 

0.00U4 

oo  1 

yy  1 

172 

o 

Q  A 

o4 

AUQ 

0  Uoo 

A  AQ 

44o 

1  O  1  1  /I  o 

lo.i  i4o 

77 
/  / 

X  X^!  1  O 

0.00  IZ 

(^i7  Q 

y/o 

173 

o 

yy 

oo 

zy 

0  in 

717 
III 

1  Q  1  ClOO 

io.iozy 

AaA 
4o4 

X  X7  0A 

0.0/  zu 

KAa 
04b 

174 

6 

AO 

OA 

TA 

^  OAQ 

0  Zoo 

AO/1 

UZ4 

1  O  1  <"iAO 

io.iyuy 

Uo 

X  XQ')7 

O.OoZ/ 

7/»0 

/  UZ 

175 

o 
o 

Uo 

OK 

Zo 

OKO 

0  ooy 

07  K 

o/o 

1  O  0007 

iO.ZZo/ 

OOO 

X  XOO  4 

o.oyo4 

A  A'7 

44/ 

176 

o 
o 

uy 

/o 

0  40i 

ma. 
1  to 

1  o  cictaA 
io.Z0D4 

0(^0 

yyz 

X  fif\Ar\ 
O.OU4U 

7Q7 

(oi 

177 

Q 

6 

1  Q 

io 

oo 

zy 

t^A  ^ 

0  040 

ooo 
Zoo 

1  O  OA,'l  1 

io.oU4i 

Q/17 

o4/ 

X  A 1  /I  A 

o.ol4o 

70/1 

/  Z4 

178 

o 
o 

1 

10 

o4 

K.  AOO 

0  boy 

7  f^O 

/  oZ 

1  O  O/l  1  A 

io.o4io 

A /I  1 

o4i 

X  AOXO 
O.oZoZ 

o^^o 
Zbo 

179 

Q 

o 

OA 

A\) 

A  1 

4i 

0   /  OO 

ooo 

ooy 

1  O  070A 

io.o/  yu 

QQO 

ooZ 

O.OOO/ 

/I  AQ 

4Uo 

180 

o 
o 

AA 
UU 

r;  Qoo 
0  OoZ 

AAA 

UUU 

1  O  A  A  £i  A 

io.4io4 

u/y 

X  A/lfiO 

0.o4oZ 

1  ^o 

ibZ 

181 

6 

07 

A  1 
Oi 

ooo 

0  yzy 

1  A  1 

/  41 

1  O  /I  xon 

1 0.40O0 

O  A 

Z4 

0.0000 

XOQ 

oZo 

182. 

o 
o 

oi 

O^l 

Z4 

A  AOQ 

0  UZo 

f;AQ 
ooo 

1  O  /I  OA7 

io.4yU7 

07  A 
O/O 

O.OO/U 

XI  1 

oil 

183 

Q 

o 

Q  1 

QO 

©y 

A   1  OU 
0  iZo 

/1Q7 

4o/ 

1  O  XO'7'7 

io.oZ// 

A  OO 

4yo 

X  A    "7  1 

0.0/  /  4 

11/1 
114 

184 

Q 

o 

QQ 
OO 

00 

A  OOQ 

0  zzy 

0U4 

io.oo4o 

a 
0 

X  AQTT 
0.00/  7 

OA 

o4 

185 

Q 

o 

/I  0 

Ao 

A  QQ1 

0  ooi 

AOs; 
oZO 

t  o  ant  A 
io.oU14 

7  AX 

/Uo 

X  ^JOOA 

o.byoU 

1  oo 

lyz 

186 

Q 

o 

40 

yo 

A  /I  Q/1 
O  4o4 

OOO 

1  o  aoQ  t 
io.Dool 

Q 1  7 

oi  / 

X  TAOO 

0./  UoZ 

b/0 

187 

Q 

o 

4y 

AO 

oy 

A  f^QQ 

0  Ooy 

OAO 

ZUo 

1  o  a '7  17 

10.0/4/ 

O/l  o 

y4o 

X  71  O  1 

0./  io4 

"OI 

/  yi 

188 

Q 

o 

Oo 

44 

A  A/1/1 
0  044 

A70 
0/  Z 

1  Q  71  1  O 

io./  ilo 

AOO 

uyz 

X  700£! 

0./  Zob 

X  /I  o 

o4o 

189 

Q 

0/ 

Zi 

A 

0  /Oi 

OAO 

zby 

1  O  7/177 

io./4/  / 

071 

Z/  i 

X  'TOO'? 

0./O07 

oo^ 

yob 

190 

Q 
O 

AA 
UU 

0  ooy 

AAA 

UUU 

1  O  7  Q  1 A 

io./o4U 

1  QQ 

4oo 

X  ^  1  oo 
0./  4oo 

071 

y/  i 

191* 

Q 
O 

o4 

Q1 
oi 

A  OA7 

0  yo/ 

Q7  1 

o/ 1 

1  O  OOAO 

io.oZUZ 

75 

X  XOO 

0./  ooy 

^  X  o 

bcZ 

192 

Q 

o 

Oo 

A/1 
04 

7  A77 

/  u/  / 

QQQ 
OOO 

1  O  o  r:  ,1 
io.(5004 

A£i  X 

Uoo 

5.7689 

ooo 

yoz 

193 

Q 

o 

70 

/  A 

AQ 

4y 

7    1  QO 

/  ioy 

AX7 

Uo/ 

1  O  OOO/I 

io.oyZ4 

4 

X  ""7  00 

0./  /  oy 

c\£ia 

ybb 

194 

Q 

i  0 

QA 
OO 

7  QA1 

/  oUi 

OQ/1 

oo4 

1  o  nooo 

io.yzoo 

ooo 
ooo 

5.7889 

bU4 

195 

o 
O 

QA 

OX 

Zo 

7  /111 

/  4i4 

07  K 
O/O 

13.9642 

4 

5.7988 

9 

196 

Q 
O 

o4 

1  A 

io 

7  r:oo 

/  ozy 

OOO 

1  A 

14. 

5.8087 

857 

197 

o 
O 

QQ 
OO 

AO 

uy 

7  A/1 

/  04^ 

070 

o/o 

14.0356 

688 

5.8186 

479 

198 

Q 

o 

OO 

yz 

A  i 

U4 

7  7/:;o 
/  /  oZ 

ono 

oyz 

14.0712 

473 

5.8284 

867 

199 

Q 
O 

o/? 

yo 

A1 

Ui 

7  880 

599 

14.1067 

36 

5.8382 

725 

200 

4 

00 

00 

8  000 

000 

14.1421 

356 

5.8480 

355 

201 

U4 

A1 
Ui 

Q   1  OA 

o  iZU 

AA1 

oUl 

1/1  1  4 

J4.i/  /4 

1  i30 

4oy 

5.8577 

aa 
bb 

202 

4 

08 

04 

8  242 

408 

14.2126 

704 

5.8674 

673 

203 

4 

12 

09 

8  365 

427 

14.2478 

068 

5.8771 

307 

204 

4 

16 

16 

8  489 

664 

14.2828 

569 

5.8867 

653 

205 

4 

20 

25 

8  615 

125 

14.3178 

211 

5.S963 

685 

206 

4 

24 

36 

8  741 

816 

14.3527 

001 

5.9059 

406 

207 

4 

28 

49 

8  869 

743 

14.3874 

946 

5.9154 

817 

208 

4 

32 

64 

8  998 

912 

14.4222 

051 

5.9249 

921 

209 

4 

36 

81 

9  129 

329 

14.4568 

323 

5.9344 

721 

! 

THE   ENGINEER  S  HANDY-BOOK. 
TABLE  —  (Continued) 


OF  SQUARES,  CUBES,  AND  SQUARE  AND  CUBE  ROOTS,  ETC. 


Number. 

Square. 

Cube. 

Square  Root. 

Cube  Root. 

210 

A 

41 

00 

q 

9fi1 

000 

1 4  4Q1  ^ 
iTt.'iyio 

IXJl 

5.9439  22 

211 

A 

21 

Q 

Ot/O 

Q^l 

VOL 

14  i^9^8 

oy 

5.9533  418 

212 

4 

4Q 

44 

Q 

i7 

528 

128 

1 4  iifi09 

1 Q8 
1  yo 

5.9627  32 

213 

A 
rt 

uo 

9 

663 

5Q7 

1 4  KQ4.^ 

1  tJO 

5.9720  926 

214 

4 

O  1 

9 

800 

344 

14  fi987 

1t:.UZ(0  I 

^88 
000 

5.9814  24 

215 

4 

9f» 

Q 

t/OO 

Ol  o 

14  fifi98 

78^ 
/  00 

5.9907  264 

216 

A 

uu 

ou 

10 

077 

uyo 

it.uyuy 

oou 

6. 

217 

4 

70 

Oi7 

10 

X.\J 

91  R 

^1  '\ 

OlO 

14  7'-{0Q 
1 ... /  ovy 

1 QQ 
lyy 

6.0092  45 

218 

4 

94 

10 

OUV/ 

9^9 

lA  7A48 
11.  #  uio 

9^1 

ZOl 

6.0184  617 

219 

4 

7Q 

fil 

10 

4^Q 

14  7Q8fi 

Irr.  /  you 

48fi 

6.0276  502 

220 

4 

Ort 

00 

10 

X.\) 

000 

1 4  8*^9^ 

1  *.OOZiO 

Q7 
y  / 

6.0368  107 

221 

4 

oo 

41 

10 

(  t70 

8fi1 

OUl 

14  8fifi0 

Irr.OUUU 

887 
uo  / 

6.0459  435 

222 

4 

Q9 

10 

041 

048 
v^o 

14  8QQfi 
iLOfyu 

fi44 

6.0550  489 

223 

4 

rr 

Q7 

9Q 

1 1 

11 

14  Q^*^1 

o^u 

6.0641  27 

224 

o 

7f^ 

1 1 

1 1 

9^Q 

j/±.yuuu 

9QiS 

^«7U 

6.0731  779 

225 

p; 
o 

Ofi 

9^ 

1 1 

11 

^QO 

Oi/V 

lU. 

6.0822  02 

226 

o 

10 

7fi 

1 1 

1 1 

OtO 

17fi 

1  Ft  0^^9 

lU.UOOZi 

0fi4 

d\j'± 

6.0911  994 

227 

o 

1.^ 

9Q 

1 1 

1 1 

fiQ7 

Ut// 

08^ 
uoo 

lU.vUUU 

102 

6.1001  702 

228 

o 

1 Q 

84 

1 1 

11 

^^9 
ouz 

1  ^  OQQR 
lu. uyyu 

uoy 

6.1091  147 

229 

5 

94 

41 

12 

\}\jO 

Q8Q 

1    1  '^97 

4fi 

TtU 

6.1180  332 

230 

O 

9Q 

00 

1 9 
iz 

1  R7 

000 

1^1  fi^7 
lu.  1  uu  / 

uuy 

6.1269  257 

231 

o 

oo 

Ol 

19 

IZi 

ozu 

^Q1 
oyi 

lu.iyou 

849 

6.1357  924 

232 

o 

oo 

94 

19 

1  Ll 

487 

1fi8 

lUO 

1    9^1  Ft 

4R9 

6.1446  337 

233 

o 

49 

8Q 

19 
1^ 

oo  / 

lU.ZiU^O 

0/  u 

6.1534  495 

234 

5 

47 

UO 

19 

iZi 

81 9 
oiz 

Q04 

1  Ft  9Q70 

uou 

6.1622  401 

235 

5 

C>Zf 

9^^ 

1  9 
1  ^ 

Q77 

87.^ 

Ol  o 

1  ^9Q7 

lU.OZt/  / 

097 

6.1710  058 

236 

5 

1  ^ 

lO 

144 

256 

915 

6.1797  466 

237 

o 

fil 
Ul 

oy 

1  ^ 

lO 

^1  9 

Ol^ 

0^^ 
yjoo 

1  .'S  ^Q48 
lu.oyio 

04^ 

6.1884  628 

238 

o 

uo 

44 

1  ^ 

lO 

481 

■4:01 

979 

1.^  4979 

rrOU 

6.1971  544 

239 

5 

71 

91 
zi 

1  ^ 

lO 

Dt>l 

Q1 Q 
yiy 

1  Ft  4.^Qfi 

lU.TiUaU 

248 

6.2058  218 

240 

o 

7fi 

00 

1  ^ 
lo 

894 

000 

1  ^  4Q1  Q 
lu.Ttyiy 

OOrr 

6.2144  65 

241 

o 

^0 

81 

1  Q 
10 

QQ7 

1  ^  .^941 

lU.UZIl 

747 

6.2230  843 

242 

5 

85 

64 

14 

172 

488 

15.5563 

492 

6.2316  797 

243 

O 

QO 

4Q 

1 4 
1^ 

^48 
OtcO 

Q07 
yu# 

1  ^  ^^884 

lU.UOOrt 

u#  0 

6.2402  515 

244 

5 

95 

36 

14 

526 

784 

15.6204 

994 

6.2487  998 

245 

6 

00 

25 

14 

706 

125 

15.6524 

758 

6.2573  248 

246 

6 

05 

16 

14 

886 

936 

15.6843 

871 

6.2658  266 

247 

6 

10 

09 

15 

069 

223 

15.7162 

836 

6.2743  054 

248 

6 

15 

04 

15 

252 

992 

15.7480 

157 

6.2827  613 

249 

6 

20 

01 

15 

438 

249 

15.7797 

338 

6.2911  946 

250 

6 

25 

00 

15 

625 

000 

15.8113 

883 

6.2996  053 

251 

6 

30 

01 

15 

813 

251 

15.8429 

795 

6.3079  935 

THE   ENGINEER'S  HANDY-BOOK. 
TABLE  —  (Continued) 


OF  SQUARES,  CUBES,  AND  SQUARE  AND  CUBE  ROOTS,  ETC. 


XT 

Square. 

Cube 

Square  xCoot. 

Cube  Root. 

252 

6  35 

04 

16  003  008 

15.8745  079 

6.3163 

596 

253 

0  40 

09 

16  194  277 

15.9059  737 

6.3247 

035 

254 

0  45 

lo 

16  387  064 

15.9373  775 

6.3330 

256 

255 

D  OU 

oc 
LO 

16  581  375 

15.9687  194 

6.3413 

257 

256 

0  00 

oa 
OD 

16  777  216 

16. 

6.3496 

042 

257 

0  oU 

A  A 

49 

16  974  593 

16.0312  195 

6.3578 

611 

258 

0  DO 

^  A 

o4 

17  173  512 

16.0623  784 

6.3660 

968 

259 

0  7U 

»1 

17  373  979 

16.0934  769 

6.3743 

111 

260 

0  /D 

AA 

17  576  000 

16.1245  155 

6.3825 

043 

261 

o  oi 

01 

17  779  581 

16.1554  944 

0.3906 

765 

262 

0  OD 

A  A 

44 

17  984  728 

16.1864  141 

O  OAOO 

0.3988 

279 

263 

Q.  OI 

oy 

18  191  447 

16.2172  747 

6.4069 

585 

264 

0  yb 

96 

18  399  744 

16.2480  768 

6.4150 

687 

265 

T  AO 

OK 

i20 

18  609  625 

16.2788  206 

6.4231 

583 

266 

7  07 

00 

18  821  096 

16.3095  064 

6.4312 

276 

267 

OA 

89 

19  034  163 

16.3401  346 

6.4392 

767 

268 

/  lo 

O/l 

Z4 

19  248  -832 

16.3707  055 

6.4473 

057 

269 

/  Zo 

oi 

19  465  109 

16.4012  195 

6.4553 

148 

270 

1  on 

AA 
00 

19  683  000 

16.4316  767 

6.4633 

041 

271 

"7  OA 

A  1 

41 

19  902  511 

16.4620  776 

6.4712 

736 

272 

on 

/  oy 

OA 

o4 

20  123  648 

16.4924  225 

6.4792 

236 

273 

/  40 

OA 

zy 

20  346  417 

16.5227  116 

6.4871 

541 

274 

T  r:A 

/  ou 

7^i 

7d 

20  570  824 

16.5529  454 

6.4950 

653 

275 

/  OO 

OK 

ZD 

20  796  875 

16.5831  24 

6.5029 

572 

276 

/  Oi 

7A 

7o 

21  024  576 

16.6132  477 

6.5108 

3 

277 

7  ^7 
/  0/ 

OA 

29 

21  253  933 

16.6433  17 

6.5186 

839 

278 

7  70 

O  /I 

o4 

21  484  952 

16.6783  32 

6.5265 

189 

279 

7  7Q 

A  1 

41 

21  717  639 

16.7032  931 

6.5343 

351 

280 

7  Q/1 

AA 
00 

21  952  000 

16.7332  005 

6.5421 

326 

281 

7  on 

7  oy 

51 

22  188  041 

16.7630  546 

6.5499 

116 

282 

/  yo 

O/l 

z4 

22  425  768 

16.7928  556 

6.5576 

722 

283 

O  AA 
O  00 

89 

22  665  187 

16.8226  038 

6.5654 

144 

284 

8  06 

56 

22  906  304 

•16.8522  995 

6.5731 

385 

285 

ft  1  9 

zo 

23  149  125 

16.8819  43 

6.5808 

44o 

286 

8  17 

96 

23  393  656 

16.9115  345 

6.5885 

323 

287 

8  23 

69 

23  639  903 

16.9410  743 

6.5962 

023 

288 

8  29 

44 

23  887  872 

16.9705  627 

6.6038 

545 

289 

8  35 

21 

24  137  569 

17. 

6.6114 

89 

290 

8  41 

00 

24  389  000 

17.0293  864 

6.6191 

06 

291 

8  46 

81 

24  642  171 

17.0587  221 

6.6267 

054 

292 

8  52 

64 

24  897  088 

17.0880  075 

6.6342 

874 

293 

8  58 

49 

25  153  757 

17.1172  428 

6.6418 

522 

1 

THE    ENGINEER^S  HANDY-BOOK. 
TABLE  —  (Continued) 


OF  SQUARES,  CUBES,  AND  SQUARE  AND  CUBE  ROOTS,  ETC. 


Number. 

Square. 

Cube. 

Square  Root. 

Cube  Root. 

294 

8  64  36 

25  412  184 

17.1464  282 

6.6493  998 

295 

8  70  25 

25  672  375 

17.1755  64 

6.6569  302 

296 

8  76  16 

25  934  336 

17.2046  505 

6.6644  437 

297 

8  82  09 

26  198  073 

17.2336  879 

6.6719  403 

298 

8  88  04 

26  463  592 

17.2626  765 

6.6794  2 

299 

8  94  01 

26  730  899 

17.2916  165 

6.6868  831 

300 

9  00  00 

27  000  000 

17.3205  081 

6.6943  295 

301 

9  06  01 

27  270  901 

17.3493  516 

6.7017  593 

302 

9  12  04 

27  543  608 

17.3781  472 

6.7091  729 

303 

9  18  09 

27  818  127 

17.4068  952 

6.7165  7 

304 

9  24  16 

28  094  464  - 

17.4355  958 

6.7239  508 

305 

9  30  25 

28  372  625 

17.4642  492 

6.7313  155 

306 

9  36  36 

28  652  616 

17.4928  557 

6.7386  641 

307 

9  42  49 

28  934  443 

17.5214  155 

6.7459  967 

308 

9  48  64 

29  218  112 

17.5499  288 

6.7533  134 

309 

9  54  81 

29  503  609 

17.5783  958 

6.7606  143 

310 

9  61  00 

29  791  000 

-  17.6068  169 

6.7678  995 

311 

9  67  21 

30  080  231 

17.6151  921 

6.7751  69 

312 

9  73  44 

30  371  328 

17.6635  217 

6.7824  229 

313 

9  79  69 

30  664  297 

17.6918  06 

6.7896  613 

314 

9  85  96 

SO  959  144 

17.7200  451 

6.7968  844 

315 

9  92  25 

31  255  875 

17.7482  393 

6.8040  921 

316 

9  98  56 

31  554  496 

17.7763  888 

6.8112  847 

317 

10  04  89 

31  855  013 

17.8044  938 

6.8184  62 

318 

10  11  24 

32  157  432 

17.8325  545 

6.8256  242 

319 

10  17  61 

32  461  759 

17.8605  711 

6.8327  714 

320 

10  24  00 

32  768  000 

17.8885  438 

6.8399  037 

321 

10  30  41 

33  076  161 

17.9164  729 

6.8470  213 

322 

10  36  84 

33  386  248 

17.9443  584 

6.8541  24 

^323 

10  43  29 

33  698  267 

17.9722  008 

6.8612  12 

324 

10  49  76 

34  012  224 

18. 

6.8682  855 

325 

10  56  25 

34  328  125 

18.0277  564 

6.8753  433 

326 

10  62  76 

34  645  976 

18.0554  701 

6.8823  888 

327 

10  69  29 

34  965  783 

18.0831  413 

6.8894  188 

328 

10  75  84 

35  287  552 

18.1107  703 

6.8964  345 

329 

10  82  41 

35  611  289 

18.1383  571 

6.9034  359 

330 

10  89  00 

35  937  000 

18.1659  021 

6.9104  232 

331 

10  95  61 

36  264  691 

18.1934  054 

6.9173  964 

332 

11  02  24 

36  594  368 

18.2208  672 

6.9243  656 

333 

11  08  89 

36  926  037 

18.2482  876 

6.9313  088 

334 

11  15  56 

37  259  704 

18.2756  669 

6.9382  321 

335 

11  22  25 

37  595  375 

18.3030  052 

6.9451  496 

THE   engineer's  HANDY-BOOK. 

T  A  B  Li  K  —  (Continued) 


OP  SQUARES,  CUBES,  AND  SQUARE  AND  CUBE  ROOTS,  ETC. 


Number. 

Square. 

Cube. 

Square  Root. 

Cube  Root. 

336 

11 

28 

96 

37 

933 

056 

18.3303 

028 

6.9520 

533 

337 

11 

35 

69 

38 

272 

753 

18.3575 

598 

6.9589 

434 

338 

11 

42 

44 

38 

614 

472 

18.3847 

763 

6.9658 

198 

339 

11 

49 

21 

38 

958 

219 

18.4119 

526 

6.9726 

826 

340 

11 

56 

00 

39 

304 

000 

18!4390 

889 

6.9795 

321 

341 

11 

62 

81 

39 

651 

821 

18.4661 

853 

6.9863 

681 

342 

11 

69 

64 

40 

001 

688 

18.4932 

42 

6.9931 

906 

343 

11 

76 

49 

40 

353 

607 

18.5202 

592 

7. 

344 

11 

83 

36 

40 

707 

584 

18.5472 

37 

7.0067 

962 

345 

11 

90 

25 

41 

063 

625 

18.5741 

756 

7.0135 

791 

346 

11 

97 

16 

41 

421 

736 

18.6010 

752 

7.0203 

49 

347 

12 

04 

09 

41 

781 

923 

18.6279 

36 

7.0271 

058 

348 

12 

11 

04 

42 

144 

192 

18.6547 

581 

7.0338 

497 

349 

12 

18 

01 

42 

508 

549 

18.6815 

417 

7.0405 

806 

350 

12 

25 

00 

42 

875 

000 

18.7082 

869 

7.0472 

987 

351 

12 

32 

01 

43 

243 

551 

18.7349 

94 

7.0540 

041 

352 

12 

39 

04 

43 

614 

208 

18.7616 

63 

7.0606 

967 

353 

12 

46 

09 

43 

986 

977 

18^7882 

942 

7.0673 

767 

354 

12 

53 

16 

44 

361 

864 

18.8148 

877 

7.0740 

44 

355 

12 

60 

25 

44 

738 

875 

18^8414 

437 

7.0806 

988 

356 

12 

67 

36 

45 

118 

016 

18.8679 

623 

7.0873 

411 

357 

12 

74 

49 

45 

499 

293 

18!8944 

436 

7.0939 

709 

358 

12 

81 

64 

45 

882 

712 

18!9208 

879 

7.1005 

885 

359 

12 

88 

81 

46 

268 

279 

18!9472 

953 

7!l071 

937 

360 

12 

96 

00 

46 

656 

000 

18.9736 

66 

7.1137 

866 

361 

13 

03 

21 

47 

045 

831 

19. 

7.1203 

674 

362 

13 

10 

44 

47 

437 

928 

19.0262 

976 

7.1269 

36 

363 

13 

17 

69 

47 

832 

147 

1 9.0525 

589 

7.1334 

925 

364 

13 

24 

96 

48 

228 

544 

19.0787 

84 

7.1400 

37 

365 

13 

32 

25 

48 

627 

125 

19.1049 

732 

7.1465 

695 

366 

13 

39 

56 

49 

027 

896 

19.1311 

265 

7.1530 

901 

367 

13 

46 

89 

49 

430 

863 

19.1572 

441 

7.1595 

988 

368 

13 

54 

24 

49 

836 

032 

19!l833 

261 

7!l660 

957  • 

369 

13 

61 

61 

50 

243 

409 

19.2093 

727 

7.1725 

809 

370 

13 

69 

00 

50 

653 

000 

19.2353 

841 

7.1790 

544 

371 

13 

76 

41 

51 

064 

811 

19.2613 

603 

7.1855 

162 

372 

13 

83 

84 

51 

478 

848 

19.287S 

015 

7.1919 

663 

373 

13 

91 

29 

51 

895 

117 

19  3132 

079 

7.1984 

05 

374 

13 

98 

76 

52 

313 

624 

19.3390 

796 

7.2048 

322 

375 

14 

06 

25 

52 

734 

375 

19.3649 

167 

7.2112 

479 

376 

14 

13 

76 

53 

157 

376 

19.3907 

194 

7.2176 

522 

377 

14 

21 

29 

53 

582 

633 

194164 

87S 

7.2240 

45 

576  THE  engineer's  handy-book. 

TABLE  —  (Continued) 


OF  SQUARES,  CUBES,  AND  SQUARE  AND  CUBE  ROOTS,  ETC 


Number. 

Square. 

Cube. 

Square  Root. 

Cube  Rooi. 

378 

14 

28 

84 

54 

010 

152 

19.4422 

221 

7.2304  268 

379 

14 

36 

41 

54 

439 

939 

19.4679 

223 

7.2367  972 

380 

14 

44 

00 

54 

872 

000 

19.4935 

887 

7.2431  565 

381 

14 

51 

61 

55 

306 

341 

19.5192 

213 

7.2495  045 

382 

14 

59 

24 

55 

742 

968 

19.5448 

203 

7.2558  415 

383 

14 

66 

89 

56 

181 

887 

19.5703 

858 

7.2621  675 

384 

14 

74 

56 

56 

623 

104 

19.5959 

179 

7.2684  824 

385 

14 

82 

25 

57 

066 

625 

19.6214 

169 

7.2747  864 

386 

14 

89 

96 

57 

512 

456 

19.6468 

827 

7.2810  794 

387 

14 

97 

69 

57 

960 

603 

19.6723 

156 

7.2873  617 

388 

15 

05 

44 

58 

411 

072 

19.6977 

156 

7.2936  33 

389 

15 

13 

21 

58 

863 

869 

19.7230 

829 

7.2998  936 

390 

15 

21 

00 

59 

319 

000 

19.7484 

177 

7.3061  436 

391 

15 

28 

81 

59 

776 

471 

19.7737 

199 

7.3123  828 

392 

15 

36 

64 

60 

236 

288 

19.7989 

899 

7.3186  114 

393 

15 

44 

49 

60 

698 

457 

19.8242 

276 

7.3248  295 

394 

15 

52 

36 

61 

162 

984 

19.8494 

332 

7.3310  369 

395 

15 

60 

25 

61 

629 

875 

19.8746 

069 

7.33/2  339 

396 

15 

68 

16 

62 

099 

136 

19.8997 

487 

7.3434  205 

397 

15 

76 

09 

62 

570 

773 

19.9248 

588 

7.3495  966 

398 

15 

84 

04 

63 

044 

792 

19.9499 

373 

7.3557  624 

399 

15 

92 

01 

63 

521 

199 

19.9749 

844 

7.3619  178 

400 

16 

00 

00 

64 

000 

000 

20. 

7.3680  63 

401 

16 

08 

01 

64 

481 

201 

20.0249 

844 

7.3741  979 

402 

16 

16 

04 

64 

964 

808 

20.0499 

377 

7.3803  227 

403 

16 

24 

09 

65 

450 

827 

20.0748 

599 

7.3864  373 

404 

16 

32 

16 

65 

939 

264 

20.0997 

512 

7.3925  418 

405 

16 

40 

25 

66 

430 

125 

20.1246 

118 

7.3986  363 

406 

16 

48 

36 

66 

923 

416 

20.1494 

417 

7.4047  206 

407 

16 

56 

49 

67 

419 

143 

20.1742 

41 

n  At  A'?  ric; 

7.4107  95 

408 

16 

64 

64 

67 

917 

312 

20.1990 

099 

7.4168  595 

409 

16 

72 

81 

68 

417 

929 

20.2237 

484 

7.4229  142 

410 

16 

81 

00 

68 

921 

000 

20.2484 

567 

7.4289  589 

411 

16 

89 

21 

69 

426 

531 

20.2731 

349 

^7  A  ct  A  f\  r\oo 

7.4349  938 

412 

16 

97 

44 

69 

934 

528 

20.2977 

831 

7.4410  189 

413 

17 

05 

69 

70 

444 

997 

20.3224 

014 

7.4470  342 

414 

17 

13 

96 

70 

957 

944 

20.3469 

899 

^7  /I  r  OA  OAA 

7.4530  399 

415 

17 

22 

25 

71 

473 

375 

20.3715 

488 

7.4590  359 

416 

17 

30 

56 

71 

991 

296 

20.3960 

781 

7.4650  223 

417 

17 

38 

89 

72 

511 

713 

20.4205 

779 

7.4709  991 

418 

J7 

47 

24 

73 

034 

632 

20.4450 

483 

7.4769  664 

419 

17 

55 

61 

73 

560 

059 

20.4694 

895 

7.4829  242 

rHE  engineer's  handy-book. 


577 


T  A  B  L  K  —  ( Continued) 


OF  SQUARES,  CUBES,  AND  SQUARE  AND  CUBE  ROOTS,  ETC. 


Number. 

Square. 

Cube. 

Square  Hoot. 

Cube  Root. 

420 

17  64  00 

74  088  000 

20.4939  015 

7.4888  724 

421 

17  72  41 

74  618  461 

20.5182  845 

7.4948  113 

422 

17  80  84 

75  151  448 

20.5426  386 

7.5007  406 

423 

17  89  29 

75  686  967 

20.5669  638 

7.5066  607 

424 

17  97  76 

76  225  024 

20.5912  603 

7.5125  715 

425 

18  06  25 

76  765  625 

20.6155  281 

7.5184  73 

426 

18  14  76 

77  308  776 

20.6397  674 

7.5243  652 

427 

18  23  29 

77  854  483 

20.6639  783 

7.5302  482 

428 

18  31  84 

78  402  752 

20.6881  609 

7.5361  221 

429 

18  40  41 

78  953  589 

20.7123  152 

7.5419  867 

430 

18  49  00 

79  507  000 

20.7364  414 

7.5478  423 

431 

18  57  61 

80  062  991 

20.7605  395 

7.5536  888 

432 

18  66  24 

80  621  568 

20.7846  097 

7.5595  263 

433 

18  74  89 

81  182  737 

20.8086  52 

7.5653  548 

434 

18  83  56 

81  746  504 

20.8326  667 

7.5711  743 

435 

18  92  25 

82  312  875 

20.8566  536 

7.5769  849 

436 

19  00  96 

82  881  856 

20.8806  13 

7.5827  865 

437 

19  09  69 

83  453  453 

20.9045  45 

7.5885  793 

438 

19  18  44 

84  027  672 

20.9284  495 

7.5943  633 

439 

19  27  21 

84  604  519 

20.9523  268 

7.6001  385 

440 

19  36  00 

85  184  000 

20.9761  77 

7.6059  049 

441 

19  44  81 

85  766  121 

21. 

7.6116  626 

442 

19  53  64 

86  350  888 

21.0237  96 

7.6174  116 

443 

19  62  49 

86  938  307 

21.0475  652 

7.6231  519 

444 

19  71  36 

87  528  384 

21.0713  075 

7.6288  837 

445 

19  80  25 

88  121  125 

21.0950  231 

7.6346  067 

446 

19  89  16 

88  716  536 

21.1187  121 

7.6403  213 

447 

19  98  09 

89  314  623 

21.1423  745 

7.6460  272 

448 

20  07  04 

89  915  392 

21.1660  105 

7.6517  247 

449 

20  16  01 

90  518  849 

21.1896  201 

7.6574  138 

450 

20'  25  00 

91  125  000 

21.2132  034 

7.6630  943 

451 

20  34  01 

91  733  851 

21.2367  .606 

7.6687  665 

452 

20  43  04 

92  345  408 

21.2602  916 

7.6744  303 

453 

20  52  09 

92  959  677 

21.2837  967 

7.6800  857 

454 

20  61  16 

93  576  664 

21.3072  758 

7.6857  328 

455 

20  70  25 

94  196  375 

21.3307  29 

7.6913  717 

456 

20  79  36 

94  818  816 

21.3541  565 

7.6970  023 

457 

20  88  49 

95  443  993 

21.3775  583 

7.7026  246 

458 

20  97  64 

96  071  912 

21.4009  346 

7.7082  388 

459 

21  06  81 

96  702  579 

21.4242  853 

1  7.7138  448 

460 

21  16  00 

97  336  000 

21.4476  106 

i  7.7194  426 

461 

21  25  21 

97  972  181 

21.4709  106 

7.7250  325 

49  2M 


578 


THE   ENGINEER'S  HANDY-BOOK. 


TABLE  —  (Continued) 


OF  SQUARES,  CUBES,  AND  SQUARE  AND  CUBE  ROOTS,  ETC. 


Number. 

Square, 

Cube. 

Square  Root. 

Cube  Root. 

462 

21 

34 

44 

98 

611 

128 

21.4941 

853 

7.7306  141 

463 

21 

43 

69 

99 

252 

847 

21.5174 

348 

7.7361  877 

464 

21 

52 

96 

99 

897 

344 

21.5406 

592 

7.7417  532 

465 

21 

62 

25 

100 

544 

625 

21.5638 

587 

7.7473  109 

466 

21 

71 

56 

101 

194 

696 

21.5870 

331 

7.7528  606 

467 

21 

80 

89 

101 

847 

563 

21.6101 

828 

7.7584  023 

468 

21 

90 

24 

102 

503 

232 

21.6333 

077 

7.7639  361 

469 

21 

99 

61 

103 

161 

709 

2L6564 

078 

7.7694  62 

470 

22 

09 

00 

103 

823 

000 

21.6794 

834 

7.7749  801 

471 

22 

18 

41 

104 

487 

111 

2L7025 

344 

7.7804  904 

472 

22 

27 

84 

105 

154 

048 

21.7255 

51 

7.7859  928 

473 

22 

37 

29 

105 

823 

817 

21.7485 

632 

7.7914  875 

474 

22 

46 

76 

106 

496 

424 

21.7715 

411 

7.7969  745 

475 

22 

56 

25 

107 

171 

875 

21.7944 

947 

7.8024  538 

476 

22 

65 

76 

107 

850 

176 

21.8174 

242 

7.8079  254 

477 

22 

75 

29 

108 

531 

333 

2l!8403 

297 

7.8133  892 

478 

22 

84 

84 

109 

215 

352 

21.8632 

111 

7.8188  456 

479 

22 

94 

41 

109 

902 

239 

21.8860 

686 

7.8242  942 

480 

23 

04 

00 

no 

592 

000 

21.9089 

023 

7.8297  353 

481 

23 

13 

61 

111 

284 

641 

2L9317 

122 

7.8351  688 

482 

23 

23 

24 

111 

980 

168 

21.9544 

984 

7.8405  949 

483 

23 

32 

89 

112 

678 

587 

21.9772 

61 

7.8460  134 

484 

23 

42 

56 

113 

379 

904 

22. 

7.8514  244 

485 

23 

52 

25 

114 

084 

125 

22.0227 

155 

7.8568  281 

486 

23 

61 

96 

114 

791 

256 

22.0454 

077 

7.8622  242 

487 

23 

71 

69 

115-  501 

303 

22.0680 

765 

7.8676  13 

488 

23 

81 

44 

116 

214 

272 

22.0907 

22 

7.8729  944 

489 

23 

91 

21 

116 

930 

169 

22.1133 

444 

7.8783  684 

490 

24 

01 

00 

117 

649 

000 

22.1359 

436 

7.8837  352 

491 

24 

10 

81 

118 

370 

771 

22!l585 

198 

7.8890  946 

492 

24 

20 

64 

119 

095 

488 

22.1810 

73 

«7*8944  468 

493 

24 

30 

49 

119 

823 

157 

22  20.S6 

033 

7.8997  917 

494 

24 

40 

36 

120 

553 

784 

22.2261 

108 

7.9051  294 

495 

24 

50 

25 

121 

287 

375 

22.2485 

955 

7.9104  599 

496 

24 

60 

16 

122 

023 

936 

22!2710 

575 

7.9157  832 

497 

24 

70 

09 

122 

763 

473 

22.2934 

968 

7.9210  994 

498 

24 

80 

04 

123 

505 

992 

22.3159 

136 

7.9264  085 

499 

24 

90 

01 

124 

251 

499 

22.3383 

079 

7.9317  104 

500 

25 

00 

00 

125 

000 

000 

22.3606 

798 

7.9370  053 

501 

25 

10 

01 

125 

751 

501 

22.3830 

293 

7.9422  931 

502 

25 

20 

04 

126 

506 

008 

22.4053 

565 

7.9475  739 

503 

25 

30 

09 

127 

263 

527 

22.4276 

615 

7.9528  477 

THE   ENGINEER  .S    HANDY-BOOK.  -) 
TABLE-  (Cojitinued) 


OF  SQUARES,  CUBES,  AND  SQUARE  AND  CUBE  ROOTS,  ETC. 


Number. 

Square. 

Cube. 

Square  Root. 

Cube  Root. 

25 

40 

16 

128 

024 

064 

22.4499 

443 

7.9581 

144 

OxJO 

25 

50 

25 

128 

787 

625 

22.4722 

051 

7.9633 

743 

uuo 

25 

60 

36 

129 

554 

246 

22.4944 

438 

7.9686 

271 

ou/ 

25 

70 

49 

130 

323 

843 

22.5166 

605 

7.9738 

731 

O\jo 

25 

80 

64 

131 

096 

512 

22.5388 

553 

7.9791 

122 

25 

90 

81 

131 

872 

229 

22.5610 

283 

7.9843 

444 

OL\J 

26 

01 

00 

132 

651 

000 

22.5831 

796 

7.9895 

697 

Fi\  1 

O I  ± 

26 

11 

21 

133 

432 

831 

22.6053 

091 

7.9947 

883 

Ol  it 

26 

21 

44 

134 

217 

728 

22.6274 

17 

8. 

.^1  ^ 

26 

31 

69 

135 

005 

697 

22.6495 

033 

8.0052 

049 

26 

41 

96 

135 

796 

744 

22.6715 

681 

8.0104 

032 

.M  ^ 

OyO 

26 

52 

25 

136 

590 

875 

22.6936 

114 

8.0155 

946 

fil  ft 

26 

62 

56 

137 

388 

096 

22.7156 

334 

8.0207 

794 

.^17 

26 

72 

89 

138 

188 

413 

22.7376 

340 

8.0259 

574 

UIO 

26 

83 

24 

138 

991 

832 

22.7596 

134 

8.0311 

287 

26 

93 

61 

139 

798 

359 

22.7815 

715 

8.0362 

935 

27 

04 

00 

140 

608 

000 

22.8035 

085 

8.0414 

515 

521 

27 

14 

41 

141 

420 

761 

22.8254 

244 

8.0466 

03 

.599 

27 

24 

84 

142 

236 

648 

22.8473 

193 

8.0517 

479 

27 

35 

29 

143 

055 

667 

22.8691 

933 

8.0568 

862 

.594. 

27 

45 

76 

143 

877 

824 

22.8910 

463 

8.0620 

18 

.59,5 

27 

56 

25 

144 

703 

125 

22.9128 

785 

8.0671 

432 

27 

66 

76 

145 

531 

576 

22.9346 

899 

8.0722 

62 

.597 

27 

77 

29 

146 

363 

183 

22.9564 

806 

8.0773 

743 

.598 

27 

87 

84 

147 

197 

952 

22.9782 

506 

8.0824 

8 

.59Q 

27 

98 

41 

148 

035 

889 

23. 

8.0875 

794 

28 

09 

00 

148 

877 

000 

23.0217 

289 

8.0926 

723 

531 

28 

19 

61 

149 

721 

291 

23.0434 

372 

8.0977 

589 

532 

28 

30 

24 

150 

568 

768 

23.0651 

252 

8.1028 

39 

533 

28 

40 

89 

151 

419 

437 

23.0867 

928 

8.1079 

128 

534 

28 

51 

56 

152 

273 

304 

23.1084 

4 

8.1129 

803 

535 

28 

62 

25 

153 

130 

375 

23.1300 

67 

8.1180 

414 

536 

28 

72 

96 

153 

990 

656 

23.1516 

738 

8.1230 

962  , 

,5^7 

28 

83 

69 

154 

854 

153 

23.1732 

605 

8.1281 

447 

ooo 

28 

94 

44 

155 

720 

872 

23.1948 

37 

8.1331 

87 

539 

29 

05 

21 

156 

590 

819 

23.2163 

735 

8.1382 

23 

540 

29 

16 

00 

157 

464 

000 

23.2379 

001 

8.1432 

529 

541 

29 

26 

81 

158 

340 

421 

23.2594 

067 

8.1482 

765 

542 

29 

37 

64 

159 

220 

088 

23.2808 

935 

8.1532 

939 

543 

29 

48 

49 

160 

103 

007 

23.3023 

604 

8.1583 

051 

544 

29 

59 

36 

160 

989 

184 

23.3238 

076 

8.1633 

102 

545 

29 

70 

25 

161 

878 

625 

23.3452 

351 

8.1683 

092 

riiE  engineer's  handy-book. 

TABLE  —  (Continued) 


OF  SQUARES,  CUBES,  AND  SQUARE  AND  CUBE  ROOTS,  ETC. 


Number. 

Square. 

Cube. 

Square  Root. 

Cube  Root. 

546 

29 

81 

16 

162 

771 

336 

23.3666 

429 

8.1733  02 

547 

29 

92 

09 

163 

667 

323 

23.3880 

311 

8.1782  888 

548 

30 

03 

04 

164 

566 

592 

23.4093 

998 

8.1832  695 

549 

30 

14 

01 

165 

469 

149 

23.4307 

49 

8.1882  441 

550 

30 

25 

00 

166 

375 

000 

23.4520 

788 

8.1932  127 

551 

30 

36 

01 

167 

284 

151 

23.4733 

892 

8.1981  753 

552 

30 

47 

04 

168 

196 

608 

23.4946 

802 

8.2031  319 

553 

30 

58 

09 

169 

112 

377 

23.5159 

52 

8.2080  825 

554 

30 

69 

16 

170 

031 

464 

23.5372 

046 

8.2130  271 

555 

30 

80 

25 

170 

953 

875 

23.5584 

38 

8.2179  657 

556 

30 

91 

36 

171 

879 

616 

23.5796 

522 

8.2228  985 

557 

31 

02 

49 

172 

808 

693 

23.6008 

474 

8.2278  254 

558 

31 

13 

64 

173 

741 

112 

23.6220 

236 

8.2327  463 

559 

31 

24 

81 

174 

676 

879 

23.6431 

808 

8.2376  614 

560 

31 

36 

00 

175 

616 

000 

23^6643 

191 

8.2425  706 

561 

31 

47 

21 

176 

558 

481 

23.6854 

386 

8.2474  74 

562 

31 

58 

44 

177 

504 

328 

23.7065 

392 

8.2523  715 

563 

31 

69 

69 

178 

453 

547 

23.7276 

21 

8.2572  635 

'564 

31 

80 

96 

179 

406 

144 

23.7486 

842 

8.2621  492 

565 

31 

92 

25 

180 

362 

125 

23.7697 

286 

8.2670  294 

566 

32 

03 

56 

181 

321 

496 

23.7907 

545 

8.2719  039 

567 

32 

14 

89 

182 

284 

263 

23.8117 

618 

8.2767  726 

568 

32 

26 

24 

183 

250 

432 

23.8327 

506 

8.2816  255 

569 

32 

37 

61 

184 

220 

009 

23.8537 

209 

8.2864  928 

570 

32 

49 

00 

185 

193 

000 

23.8746 

728 

8.2913  444 

571 

32 

60 

41 

186 

169 

411 

23.8956 

063 

8.2961  903 

572 

32 

71 

84 

187 

149 

248 

23,9165 

215 

8.3010  304 

573 

32 

83 

29 

188 

132 

517 

23.9374 

184 

8.3058  651 

574 

32 

94 

76 

189 

119 

224 

23.9582 

971 

8.3106  941 

575 

33 

06 

25 

190 

109 

375 

23.9791 

576 

8.3155  175 

576 

33 

17 

76 

191 

102 

976 

24. 

8i3203  353 

577 

33 

29 

29 

192 

100 

033 

24.0208 

243 

8.3251  475 

578 

33 

40 

84 

193 

100 

552 

24^0416 

306 

8.3299  542 

579 

66 

A  1 

41 

194 

104 

ooy 

OA  f\£iCtA 

z4.Udz4 

1  OQ 

loo 

8.3347  553 

580 

33 

64 

00 

195 

112 

000 

24.0831 

891 

8.3395  509 

581 

33 

75 

61 

196 

122 

941 

24.1039 

416 

8.3443  41 

582 

33 

87 

24 

197 

137 

368 

24.1246 

762 

8.3491  256 

583 

33 

98 

89 

198 

155 

287 

24.1453 

929 

8.3539  047 

584 

34 

10 

56 

199 

176 

704 

24.1660 

919 

8.3586  784 

585 

34 

22 

25 

200 

201 

625 

24.1867 

732 

8.3634  466 

586 

34 

33 

96 

201 

230 

056 

24.2074 

369 

8.3682  095 

587 

■ 

34 

45 

69 

202 

262 

003 

24.2280 

829 

8.3729  668 

THE    ENGINEEK'8    HANDY-iiOOK.  58 

T  A  B      E  -  {Concluded) 


OF  SQUARES,  CUBES,  AND  SQUARE  AND  CUBE  ROOTS,  ETC. 


Number. 

Square. 

Cube. 

Square  Root. 

Cube  Root. 

588 

34 

57  44 

203 

297 

472 

24.2487 

113 

8.3777 

188 

589 

34 

69  21 

204 

336 

469 

24.2693 

222 

8.3824 

653 

590 

34 

81  00 

205 

379 

000 

24.2899 

156 

8.3872 

065 

591 

34 

92  81 

206 

425 

071 

24.3104 

916 

8.3919 

423 

592 

35 

04  64 

207 

474 

688 

24.3310 

501 

8.3966 

729 

593 

35 

16  49 

208 

527 

857 

24.3515 

913 

8.4013 

981 

594 

35 

28  36 

209 

584 

584 

24.3721 

152 

8.4061 

180 

595 

35 

40  25 

210 

644 

875 

24.3926 

218 

8.4108 

326 

596 

35 

52  16 

211 

708 

736 

24.4131 

112 

8.4155 

419 

597 

35 

64  09 

212 

776 

173 

24.4335 

834 

8.4202 

46 

598 

35 

76  04 

213 

847 

192 

24.4540 

385 

8.4249 

448 

599 

35 

88  01 

214 

921 

799 

24.4744 

765 

8.4296 

383 

600 

36 

00  00 

216 

000 

000 

24.4948 

974 

8.4343 

267 

601 

36 

12  01 

217 

081 

801 

24.5153 

013 

8.4390 

098 

602 

36 

24  04 

218 

167 

208 

24.5356 

883 

8.4436 

877  ' 

603 

36 

36  09 

219 

256 

227 

24.5560 

583 

8.4483 

605 

604 

36 

48  16 

220 

348 

864 

24.5764 

115 

8.4530 

281 

605 

36 

60  25 

221 

445 

125 

24.5967 

478 

8.4576 

906 

606 

36 

72  36 

222 

545 

016 

24.6170 

673 

8.4623 

479 

607 

36 

84  49 

223 

648 

543 

24.6373 

7 

8.467 

608 

36 

96  64 

224 

755 

712 

24.6576 

56 

8.4716 

471 

609 

37 

08  81 

225 

866 

529 

24.6779 

254 

8.4762 

892 

610 

37 

21  00 

226 

981 

000 

24.6981 

781 

8.4809 

261 

611 

37 

33  21 

228 

099 

131 

24.7184 

142 

8.4855 

579 

612 

37 

45  44 

220 

220 

928 

24.7386 

338 

8.4901 

848 

613 

37 

57  69 

230 

346 

397 

24.7588 

368 

8.4948 

065 

614 

37 

69  96 

231 

475 

544 

24.7790 

234 

8.4994 

233 

615 

37 

82  25 

232 

608 

375 

24.7991 

935 

8.5040 

35 

616 

37 

94  56 

233 

744 

896 

24.8193 

473 

8.5086 

417 

617 

38 

06  89 

234 

885 

113 

24.8394 

847 

8.5132 

435 

618 

38 

19  24 

236 

029 

032 

24.8596 

058 

8.5178 

403 

619 

38 

31  61 

237 

176 

659 

24.8797 

106 

8.5224 

321 

620 

38 

44  00 

238 

328 

000 

24.8997 

992 

8.5270 

189 

Any  number  multiplied  into  itself  3  times  is  cubed ;  as,  3  x  3  x  ■ 
=  27,  which  is  the  cube  of  3. 

The  square  root  of  any  number  is  that  number  which,  multi 
plied  into  itself,  will  be  equal  to  the  given  number;  as,  v/9  =  3  x  3 
hence  3  is  the  square  root  of  9. 


THE   ENG1NKER\s  HANDY-BOOK. 


583 


The  Wetherill  Corliss  Steani-Engine. 

The  cut  on  opposite  page  gives  an  outline  of  the  general 
appearance  of  the  Corliss  Engine  as  built  by  Robert  Wetherill 
.&  Co.,  Chester. 

The  Main  Bed  is  shaped  in  the  strongest  form  and  in  direct 
centreline  connecting  up  cylinder  and  pedestals.  The  main  ped- 
estal bearings  are  made  in  four  parts,  adjustable.  All  bearings 
and  wearing  surfaces  are  arranged  to  take  up  lost  motion  occa- 
sioned by  wear.  The  proportions,  weights,  and  strength  of  mate- 
rial are  ample.  Cylinders  are  made  of  hard,  strong,  charcoal  iron, 
and  have  all  large  proportioned  port  openings,  which  gives  the 
full  boiler  pressure  against  the  piston.  The  cross-head  is  of  an 
improved  pattern,  which  takes  a  direct  bearing  between  centre 
of  shoes,  and  the  shoes  are  gibbed  in  such  a  manner  that  they  can 
be  easily  removed  or  any  lost  motion  taken  up.  Shafts,  connecting- 
rods,  and  all  forgings  are  made  of  double-worked  hammered  iron. 
Piston-rods,  crank-pins,  and  all  other  small  pins  and  valve- 
motion  forgings,  are  of  steel.  Valve-stems,  crank-pin  boxes,  and 
valve-gear  brasses  are  all  of  bronze  metal. 

The  Governor  is  of  the  regular  Corliss  pattern  with  improve- 
ments, but  does  not  require  the  oil  or  molasses  pot  generally  used. 
It  acts  free  under  varying  loads  and  pressures,  and  regulates  closely 
from  one  horse-power  up  to  the  full  capacity  of  engine. 

Piston  is  self-packing,  and  does  not  require  any  attention  from 
the  engineer.  It  keeps  the  cylinder  in  good  order,  requires  very 
little  lubrication,  and  has  a  reputation  of  running  eight  years 
night  and  day  without  any  attention,  keeping  in  good  order  and 
steam-tight. 

Vacuum  Dash- Pots  for' closing  valves  are  generally  used.  On 
slow  running  engines,  weights  closed  with  air-cushion  are  pre- 
ferred. 

Graduating  Oil-Cups  on  all  wearing  surfaces,  and  self-feeding 
oil-cups  for  cylinders. 


584 


THE   ENGINEER'S  HANDY-BOOK. 


Emergencies. 

If  a  follower- plate  should  break  at  sea,  it  juight  be  repaired 
with  boiler-plate  and  tap-bolts,  providing  these  materials  were  on 
board  ;  if  not,  the  propeller-shaft  should  be  detached,  and  the  ship 
proceed  to  the  nearest  port,  under  sail. 

If  the  air-pump  rod  should  break,  and  no  extra  rod  be  on 
board  the  vessel,  remove  the  air-pump  bucket  and  foot-valve,  rig 
a  temporary  exhaust-pipe  with  lumber,  and  proceed  to  the  nearest 
port. 

If  a  cylinder- head  should  be  fractured  or  split,  it  might  be  re- 
paired temporarily  by  wrought-iron  bars,  canvas,  or  other  packing, 
and  tap-bolts. 

If  the  cut-oflF  valve  should  break  at  one  end,  remove  it  from 
the  other  end,  and  use  steam  at  whole  stroke. 

If  the  condenser  should  become  so  much  out  of  order  as  to 
render  it  useless,  detach  the  exhaust-pipe  from  it,  and  rig  a  tem- 
porary exhaust  with  such  materials  as  can  be  found  on  board. 

If  the  crank-pin  or  truss-block  should  heat  excessively,  allow  a 
stream  of  water  to  run  on  them  continually. 

If  the  foot- valve  should  be  rendered  useless,  the  air-pump  will 
work,  providing  the  discharge  is  in  good  order.  Foot-valves  are 
generally  made  of  vulcanized  India-rubber. 

If  the  delivery-pipe  should  break,  burst,  or  split,  it  may  be  re- 
paired temporarily  with  India-rubber  or  canvas,  lumber,  and 
ropes. 

If  a  crank-pin  should  break,  the  broken  part  may  be  removed 
and  replaced  by  a  new  one,  providing  there  is  an  extra  pin  on 
hand ;  if  not,  detach  the  propeller  and  proceed  under  sail. 

If  the  propeller-shaft  should  twist  off,  disconnect  the  engines 
from  it  and  proceed  under  sail ;  but  if  one  or  more  of  the  blades 
should  break  off,  proceed  the  best  way  you  can,  as,  while  any  por- 
tion of  it  remains,  it  is  better  than  none  at  all. 


THE    engineer's    HANDY-BOOK.  585 

Questions, 

THE  ANSWERS  TO  WHICH  WILL  BE  FOUND  IN  THE  TEXT. 

What  is  the  pressure  of  the  atmosphere  at  sea-level  ? 

Give  the  estimated  height  of  the  atmosphere. 

Give  the  component  parts  of  atmospheric  air. 

State  the  difference  in  weight  between  air,  water,  and  mercury. 

Does  the  pressure  of  the  atmosphere  differ  in  different  locali- 
ties? 

Is  the  pressure  of  the  atmosphere  constant  in  the  same  lo- 
cality ? 

Give  the  altitude  of  some  of  the  highest  mountains  in  the 
world. 

Give  the  names  of  the  highest  waterfalls  in  the  world. 

Give  the  formula  for  finding  the  horse-power  of  wind-storms. 

Give  the  meaning  of  the  term  fuel. 

Give  the  component  parts  of  various  kinds  of  fuel. 

Give  the  comparative  values  of  various  kinds  of  wood  for  the 
purpose  of  fuel  as  compared  with  coal. 

Give  the  definitions  of  the  terms  fire  and  smoke. 

Define  the  term  heat. 

Give  the  specific  heat  of  different  substances. 

Give  the  conductive  properties  of  different  substances. 

Define  the  terms  combustion  and  spontaneous  combustion. 


586  THE   ENGINEER'S  HANDY-BOOK. 

Give  the  component  parts  of  fresh  water. 

Is  the  specific  gravity  of  all  waters  the  same? 

Give  the  latent  heat  of  water,  ice,  and  steam. 

Define  the  term  vapor. 

Give  the  meaning  of  the  term  gases. 

What  is  meant  by  the  term  area? 

Give  the  rules  for  finding  the  diameters,  circumferences,  and 

areas  of  circles. 

Give  the  meaning  of  the  term  cipher. 
Give  the  meaning  of  the  terms  atoms  and  molecules. 
What  advantages  does  decimal  arithmetic  possess? 
What  are  decimal  fractions? 

Give  an  explanation  of  the  difierent  recognized  units,  such  as 
those  of  heat,  length,  surface,  capacity,  weight,  time,  velocity, 
work,  and  pressure. 

Give  the  different  lengths  which  have  been  recognized  in  Eng- 
land since  the  sixteenth  century. 

Demonstrate  the  diflference  between  vulgar  and  decimal  frac- 
tions. 

Give  the  decimals  for  the  16th  or  32d  part  of  an  inch. 


THE   engineer's   HANDY-BOOK.  587 


PART  EIGHTH. 


Lexicon  of  Definitions  of  Central,  Mechanical,  and  Djuaml- 

cal  Forces. 

Acceleration. —  Acceleration  is  the  increase  of  velocity  in  a 
moving  body,  caused  by  the  continued  action  of  the  motive  force. 
When  bodies  in  motion  pass  through  equal  spaces  in  equal  time, 
or,  in  other  words,  when  the  velocity  of  the  body  is  the  same  dur- 
ing the  period  that  the  body  is  in  motion,  it  is  termed  uniform 
motion,  of  which  we  have  a  familiar  instance  in  the  motion  of  the 
hands  of  a  clock  over  the  face  of  it;  but  a  more  correct  illustra- 
tion is  the  revolution  of  the  earth  on  its  axis.  In  the  case  of 
a  body  moving  through  unequal  spaces  in  equal  times,  or  with  a 
varying  velocity,  if  the  velocity  increase  with  the  duration  of  the 
motion,  it  is  termed  accelerated  motion ;  but,  if  it  decrease  with 
the  duration  of  the  motion,  it  is  termed  retarded  motion. 

Affinity. —  Affinity  is  a  term  used  in  chemistry  to  denote  that 
kind  of  attraction,  by  which  the  particles  of  different  bodies 
unite,  and  form  a  compound,  possessing  properties  distinct  from 
those  of  any  of  the  substances  which  compose  it.  Thus,  when  an 
acid  and  alkali  combine,  a  new  substance  is  formed  called  a  salt, 
perfectly  different  in  its  chemical  properties  from  either  an  acid 
or  an  alkali ;  and,  in  consequence  of  the  law  of  affinity,  these 
bodies  have  a  tendency  to  unite. 

Angle. —  If  two  lines,  drawn  on  a  plain  surface,  are  so  situated 
that  they  meet  in  a  point,  or  would  do  so,  if  sufficiently  prolonged, 
they  form  an  opening,  which  is  called  an  angle.  One  straight 
line,  meeting  another  which  is  perpendicular  to  it,  makes  the 
angle  on  both  sides  equal ;  then  these  angles  are  each  called  a 
right  angle,  and,  in  this  case,  the  one  line  is  said  to  be  perpen- 
dicular to  the  other,  or,  in  the  language  of  mechanics,  the  one 
line  is  said  to  be  square  with  the  other ;  and  if  the  one  line  be 
horizontal,  the  perpendicular  is  said  to  be  plumb  to  it.    The  arc,. 


588         THE  engineer's  handy-book. 

which  measures  a  right  angle,  is  the  quarter  of  the  whole  circum- 
ference, or  a  quadrant,  and  contains  90  degrees ;  any  angle  meas- 
ured by  an  arc  less  than  this  is  acute  (sharp),  and  if  by  an  arc 
greater  than  a  quadrant,  obtuse  (blunt). 

Axle. —  An  axle  is  a  shaft  supporting  a  wheel;  the  wheel  may 
turn  on  the  axle,  or  be  fastened  to  it,  and  the  axle  turn  on  bear- 
ings. Axles  are  viewed  as  having  certain  relations  to  girders  in 
principle.  Girders  generally  have  their  two  ends  resting  on  two 
points  of  support,  and  the  load  is  either  located  at  fixed  distances 
from  the  props,  or  dispersed  over  the  whole  surface  of  the  axle ; 
the  wheels  may  be  considered  the  props,  and  the  journals  the 
loaded  parts.  It  is  found  that  the  inclined  surface  of  the  wheel- 
tire,  given  by  coning  ranges  from  1  to  12  to  1  to  20;  and,  as  a 
matter  of  course,  the  direct  tendency  of  the  wheel  under  a  load  is 
to  descend  that  incline,  so  that  every  vertical  blow,  which  the 
wheels  may  receive,  is  compounded  of  two  forces,  viz.,  the  one  to 
crush  the  wheels  in  the  direction  of  their  vertical  plane,  and  the 
other  to  move  the  lower  parts  of  the  wheels  together.  It  will  be 
seen  that  these  two  forces  have  a  direct  tendency  to  bend  the  axle 
somewhere  between  the  wheels. 

Attraction. —  The  terms  attraction,  or  affinity,  and  repulsion,  in 
the  language  of  modern  scientists,  are  employed  merely  as  the  ex- 
pression of  one  of  two  general  facts,  either  that  the  masses  or  parti- 
cles of  matter  have  a  tendency  to  approach  and  unite  to,  or  to  recede 
from,  one  another,  under  certain  circumstances.  The  term  attraction 
is  used  synonymously  with  affinity.  All  bodies  have  a  tendency 
to  attract  each  other,  more  or  less,  and  it  is  this  power  which  is 
called  attraction.  Attraction  is  mutual;  it  extends  to  indefinite 
distances.  All  bodies,  whatever,  as  well  as  their  component  ele- 
mentary particles,  are  endued  with  it.  It  is  not  annihilated,  at 
however  great  a  distance  we  suppose  them  to  be  placed  from  each 
other ;  neither  does  it  disappear,  though  they  be  arranged  ever  so 
near  each  other.  The  nature  of  this  reciprocal  attraction,  or  at 
least  the  cause  which  produces  it,  is  altogether  unknown  to  us. 
Whether  it  be  inherent  in  all  matter,  or  whether  it  be  the  conse- 


THE   engineer's  HANDY-BOOK. 


589 


quence  of  some  other  agent,  are  questions  beyond  the  reach  of 
human  understanding;  but  its  existence  is  nevertheh»ss  certain. 

Capillary  Attraction. —  Capillary  attraction  is  the  property  in- 
herent in  narrow  tubes  and  porous  substances,  such  as  sponge, 
lamp-wicking,  thread,  etc.,  of  raising  oil,  water,  or  other  fluids 
above  their  natural  level.  Hence  this  principle  is  applied  for 
obtaining  a  continuous  supply  of  lubricating  fluids  between  rub- 
bing and  revolving  surfaces  in  motion,  by  means  of  a  siphon  con- 
structed of  wickings,  worsted,  or  some  other  substance,  one  end 
of  which  is  immersed  in  oil,  and  the  other  inserted  in  the  tube 
through  which  the  fluid  is  to  be  conducted. 

Centre  of  Gravity, — The  forces  with  which  all  bodies  tend  to 
fall  to  the  earth  may  be  considered  parallel ;  hence  every  body 
may  be  considered  as  acted  on  by  a  system  of  parallel  forces  whose 
resultant  may  be  found,  and  these  forces,  in  all  positions  of  the 
body,  act  on  the  same  points  in  the  same  vertical  direction.  There 
is,  therefore,  in  every  body  a  point  through  which  the  resultant 
always  passes,  in  whatever  position  it  is  placed.  This  point  is 
called  the  centre  of  gravity  of  the  body.  The  centre  of  gravity 
of  a  uniform  cylinder  or  prism  is  in  its  axis,  and  at  the  middle  of 
its  length  ;  of  a  right  cone  or  a  pyramid  it  is  also  in  the  axis,  but 
at  one-fourth  of  the  height  from  the  base. 

Cohesion.  — Cohesion  is  that  quality  of  the  particles  of  a  body 
which  causes  them  to  adhere  to  each  other,  and  to  resist  being 
torn  apart. 

Dynamics. — Dynamics  is  that  branch  of  mechanics  which 
treats  of  forces  in  motion  producing  power  and  work.  It  compre- 
hends the  action  of  all  kinds  of  machinery,  manual  and  animal 
labor,  in  the  transformation  of  physical  work. 

Elastic  Fluids.  —  Elastic  fluids  are  divided  into  two  classes  — 
permanent  gases  and  vapors.  The  gases  cannot  be  converted  into 
the  liquid  state  by  any  known  practicable  process ;  whereas  the 
vapors  are  readily  reduced  to  the  liquid  form  by  pressure  or  dim- 
inution of  temperature.  In  respect  of  their  mechanical  properties, 
there  is,  however,  no  essential  difference  between  the  two  classes. 
bO 


590 


THE   ENGINEER'S  HANDY-BOOK. 


Elastic  fluids,  in  a  state  of  equilibrium,  are  subject  to  the  action 
of  two  forces,  namely,  gravity,  and  a  molecular  force  acting  from 
particle  to  particle. 

Elasticity.  — Elasticity  is  that  quality  which  enables  a  body  to 
return  to  its  original  form,  after  having  been  distorted  or  stretched 
by  some  external  force.  The  limit  of  elasticity  is  the  extent  to 
which  any  material  may  be  stretched  without  receiving  a  perma- 
nent set. 

Energy.  — This  term  has  become  obsolete  in  a  mechanical  point 
of  view,  and  is  now  only  applied  to  the  action  of  men  and  animals. 
If  an  individual  man,  horse,  ox,  or  other  animal  performed  a  cer- 
tain amount  of  work  in  less  time  than  another  would  occupy  in 
doing  the  same  work,  we  say  that  he  acted  with  great  energy ;  but 
when  a  machine  runs  fast,  or  fire  burns  fast,  or  the  waves  roll  fast, 
we  do  not  apply  the  term  energy,  but  simply  say  that  the  machine 
runs  at  a  very  high  speed,  or  increased  its  speed;  or  the  fire 
burned  fiercely,  or  that  the  wind  blew,  or  the  waves  rolled  with 
great  violence. 

Force.  — Force  is  the  cause  of  motion  or  change  of  motion  in 
material  bodies.  Every  change  of  motion,  viz.,  every  change  in 
the  velocity  of  a  body,  must  be  regarded  as  the  efiect  of  a  force. 
On  the  other  hand,  rest,  or  the  invariability  of  the  state  of  motion 
of  a  body,  must  not  be  attributed  to  the  absence  of  forces,  since  op- 
posite forces  destroy  each  other  and  produce  no  eflPect.  The  force 
of  gravity  with  which  a  body  falls  to  the  ground,  still  acts,  though 
the  body  rests ;  but  this  action  is  counteracted  by  the  solidity  of 
the  material  upon  which  it  reposes.  Forces  that  are  balanced  so 
as  to  produce  rest,  are  called  statical  forces  or  pressures,  to  dis- 
tinguish them  from  moving,  deflecting,  accelerating,  or  retarding 
forces,  {.  e,,  such  as  are  producing  motion,  or  a  change  in  the 
direction  or  velocity  of  motion.  This  distinction  is  wholly  arti- 
ficial, as  the  same  force  may  act  in  any  of  these  modes ;  it  may 
sometimes  be  a  statical  and  sometimes  an  accelerating  force. 

Force  is  any  action  which  can  be  expressed  simply  by  weight, 
and  is  distinguished  by  a  great  variety  of  terms,  such  as  attraction, 


THE   ENGINEEIl\s  HANDY-BOOK. 


591 


repulsion,  gravity,  pressure,  tension,  compression,  cohesion,  adhe- 
sion, resistance,  inertia,  strain,  stress,  strength,  thrust,  burden,  load, 
squeeze,  pull,  push,  pinch,  punch,  etc.,  all  of  which  may  be  meas- 
ured or  expressed  by  weight  without  regard  to  motion,  time, 
power,  or  work. 

Focus.  — Focus  in  geometry  is  that  point  in  the  transverse  axis 
of  a  conic  section,  at  which  the  double  ordinate  is  equal  to  a  per- 
imeter, or  to  a  third  proportional  to  the  transverse  and  conjugate 
axis. 

Friction.  — Friction  is  the  resistance  offered  to  the  motion  of  a 
body,  when  pressed  upon  the  surface  of  another  body  which  does 
not  partake  of  its  motion.  Under  these  circumstances,  the  sur- 
faces in  contact  have  a  certain  tendency  to  adhere.  Not  being 
perfectly  smooth,  the  imperceptible  asperities  w^hich  may  be  sup- 
posed to  exist  on  all  surfaces,  however  highly  polished,  become  to 
some  extent  interlocked,  and,  in  consequence,  a  certain  amount  of 
force  is  requisite  to  overcome  the  mutual  resistance  to  motion  of 
the  two  surfaces,  and  to  maintain  the  sliding  motion  even  when  it 
has  been  produced.  By  increasing  the  pressure,  the  resistance  to 
motion  is  increased  also  ;  and  on  the  other  hand,  by  rendering  the 
surfaces  smoother  by  lubrication,  its  amount  is  greatly  diminished, 
but  can  never  be  entirely  annulled. 

Friction  cannot  be  strictly  called  a  force,  unless  that  term  be 
taken  in  a  negative  sense.  The  tendency  of  force,  in  the  rigid 
meaning  of  the  word,  is  to  produce  motion ;  whereas  the  tendency 
of  friction  is  to  destroy  motion. 

Friction  Rollers. —  The  obstruction  which  a  cylinder  meets  in 
rolling  along  a  smooth  plane,  is  quite  distinct  in  its  character,  and 
far  inferior  in  its  amount,  to  that  which  is  produced  by  the  fric- 
tion of  the  same  cylinder  drawn  lengthwise  along  a  plane.  For 
example,  in  the  case  of  w^ood  rolling  on  wood,  the  resistance  is  to 
the  pressure,  if  the  cylinder  be  small,  as  16  or  18  to  1000,  and  if 
the  cylinder  be  large,  this  may  be  reduced  to  6  to  1000.  The 
friction  from  sliding,  in  the  same  cases,  would  be  to  the  pressure  as 
2  to  10  or  3  to  10,  according  to  the  nature  of  the  wood.  Hence, 


592 


THE   ENGINEER'S  HANDY-BOOK. 


by  causing  one  body  to  roll  on  another,  the  resistance  is  dimin- 
ished from  12  to  20  times.  It  is  therefore  a  principle,  in  the 
composition  of  machines,  that  attritign  should  be  avoided  as 
much  as  possible,  and  rolling  motions  substituted  whenever  cir- 
cumstances permit. 

Gravity  and  Gravitation. —  These  terms  are  often  used  synony- 
mously, to  denote  the  mutual  tendency  which  all  bodies  in  nature 
have  to  approach  each  other.  Gravity  acts  on  gases  in  the  same 
manner  as  on  all  other  material  substances  ;  but  the  action  of  the 
molecular  forces  is  altogether  different  from  that  which  takes  place 
among  the  elementary  particles  of  solids  and  liquids,  as  in  the 
case  of  solid  bodies,  the  molecules  strongly  attract  each  other 
(hence  results  their  cohesion),  and,  in  the  case  of  liquids,  exert  a 
feeble  or  evanescent  attraction,  so  as  to  be  indifferent  to  internal 
motion ;  but,  in  the  case  of  the  gases,  the  molecular  forces  are 
repulsive,  and  the  molecules,  yielding  to  the  action  of  these  forces, 
tend  incessantly  to  recede  from  each  other,  and,  in  fact,  do  recede, 
until  their  further  separation  is  prevented  by  an  exterior  obstacle. 

Gravity,  Specific. —  The  specific  gravity  of  a  body  is  the  ratio 
of  its  weight  to  an  equal  volume  of  some  other  body  assumed  as 
a  conventional  standard.  The  standard  usually  adopted  for  solids 
and  liquids  is  rain  or  distilled  water  at  a  common  temperature. 
In  bodies  of  equal  magnitudes,  the  specific  gravities  are  directly 
as  the  weights  or  as  their  densities.  In  bodies  of  the  same  specific 
gravity  the  weights  will  be  as  the  magnitudes.  In  bodies  of  equal 
weights,  the  specific  gravities  are  inversely  as  the  magnitudes.  The 
weights  of  different  bodies  are  to  each  other  in  the  compound  ratio 
of  their  magnitudes  and  specific  gravities.  Hence,  it  is  obvious 
that,  speaking  of  the  magnitude,  weight,  and  specific  gravity  of 
a  body,  if  any  two  of  them  are  given,  the  third  may  be  found. 
A  body,  immersed  in  a  fluid,  will  sink  if  its  specific  gravity  be 
greater  than  that  of  the  fluid;  if  it  be  less,  the  body  will  rise  to 
the  top,  and  be  only  partly  immersed  ;  and,  if  the  specific  gravity 
of  the  body  and  fluid  be  equal,  it  will  remain  at  rest  in  any  part 
of  the  fluid  in  which  it  may  be  placed.    When  a  body  is  heavier 


THE   engineer's    FT  A  N  I)  V  -  H  O  O  K  . 


593 


than  a  fluid,  it  lose§  as  much  of  its  weight  when  innnersed  as  is 
equal  to  a  quantity  of  the  fluid  of  the  same  bulk  or  magnitude.  * 
If  the  specific  gravity  of  the  fluid  he  greater  than  that  of  the 
body,  then  the  quantity  of  fluid  displaced  by  the  part  immersed 
is  equal  to  the  weight  of  the  whole  body.  And  hence,  as  the 
specific  gravity  of  the  fluid  is  to  that  of  the  body,  so  is  the 
whole  magnitude  of  the  body  to  the  part  immersed.  The  spe- 
cific gravities  of  equal  solids  are  as  their  parts  immersed  in  the 
same  fluid. 

Gyration,  the  Centre  of. —  The  centre  of  gyration  is  that  point 
in  which,  if  all  the  matter  contained  in  a  revolving  system  were 
collected,  the  same  angular  velocity  will  be  generated  in  the  same 
time  by  a  given  force  acting  at  any  place,  as  would  be  generated 
by  the  same  force  acting  similarly  in  the  body  or  system  itself. 
The  distance  of  the  centre  of  gyration  from  the  point  of  suspen- 
sion or  the  axis  of  motion,  is  a  mean  proportional  between  the 
distances  of  the  centres  of  oscillation  and  gravity  from  the  same 
point  or  axle. 

Horse-power,  or  Power  of  a  Horse. —  The  power  of  a  horse 
when  applied  to  draw  loads,  as  well  as  when  made  the  standard 
of  comparison  for  determining  the  value  of  other  powers,  has 
been  variously  stated.  The  relative  strength  of  men  and  horses 
depends,  of  course,  upon  the  manner  in  which  their  strength  is 
applied.  Thus,  the  worst  w^ay  of  applying  the  strength  of  a  horse 
is  to  make  him  carry  a  weight  up  a  steep  hill.  The  power  of  a 
horse  varies  from  five  to  eleven  times  that  of  a  man. 

Hydrodynamics. —  Hydrodynamics  is  that  branch  of  general 
mechanics  which  treats  of  the  equilibrium  and  motion  of  fluids. 
The  terms  hydrostatics  and  hydrodynamics  have  a  signification 
corresponding  to  the  terms  statics  and  dynamics  in  the  mechanics 
of  solid  bodies,  viz.,  hydrostatics  is  that  division  of  the  science 
which  treats  of  the  equilibrium  of  fluids,  and  hydrodynamics  that 
which  relates  to  their  forces  and  motion.  It  is,  however,  usual  to 
include  the  w^hole  doctrine  of  the  mechanics  of  fluids  under  the 
general  term  of  hydrodynamics,  and  to  denote  the  divisions  rela- 
50*  "  2N 


594 


THE   engineer's  HANDY-BOOK. 


tive  to  their  equilibrium  and  motion  by  tha  terms  hydrostatics 
and  hydraulics. 

Hyperbola. —  A  plane  figure,  formed  by  cutting  a  section  from 
a  cone  by  a  plane  parallel  to  its  axis,  or  to  any  plane  within  the 
cone,  which  passes  through  the  cone's  vertex.    The  curve  of  the  j 
hyperbola  is  such,  tliat  the  difference,  between  the  distances  of  i 
any  point  in  it  from  two  given  points,  is  always  equal  to  a  given  ; 
right  line.    If  the  vertices  of  two  cones  meet  each  other,  so  that  i 
their  axes  form  one  continuous  straight  line,  and  the  plane  of  the 
hyperbola  cut  from  one  of  the  cones  be  continued,  it  will  cut  the 
other  cone,  and  form  what  is  called  the  opposite  hyperbola,  equal ! 
and  similar  to  the  former ;  and  the  distance,  between  the  vertices  i 
of  the  two  hyperbolae,  is  called  the  major  axis,  or  transverse  di- ' 
ameter.    If  the  distance  between  a  certain  point  within  the  hyper- 
bola, called  the  focus,  and  any  point  in  the  curve  be  subtracted  i 
from  the  distance  of  said  point  in  the  curve  from  the  focus  of  the  t 
opposite  hyperbola,  the  remainder  will  always  be  equal  to  a  given 
quantity,  that  is,  to  the  major  axis ;  and  the  distance  of  either  focus  - 
from  the  centre  of  the  major  axis  is  called  the  eccentricity.  The 
line  passing  through  the  centre,  perpendicular  to  the  major  axis, 
and  having  the  distance  of  its  extremities  from  those  of  the  axis- 
equal  to  the  eccentricity,  is  called  the  minor  axis,  or  conjugate 
diameter.    An  ordinate  to  the  major  axis,  a  double  ordinate,  and! 
an  absciss  mean  the  same  as  the  corresponding  lines  in  the  pa-; 
rabola.  | 

Impact  is  the  single  instantaneous  blow  or  stroke  communi- 
cated from  one  body  in  motion  to  another  either  in  motion  or  at 
rest. 

Impenetrability. —  In  physics,  one  of  the  essential  properties  of 
matter  or  body.  It  is  a  property  inferred  from  invariable  experi- 
ence, and  resting  on  this  incontrovertible  fact,  that  no  two  bodies 
can  occupy  the  same  portion  of  space  in  the  same  instant  of  time. 
Impenetrability,  as  respects  solid  bodies,  requires  no  proof :  it  is 
obvious  to  the  touch.  With  regard  to  liquids,  the  property  may 
be  proved  by  very  simple  experiments.    Let  a  vessel  be  filled  to 


THE    ENGINEEr\s  HANDY-BOOK. 


595 


the  brim  with  water,  and  a  solid,  incapable  of  solution  in  water, 
be  plunged  into  it ;  a  portion  of  the  water  will  overflow,  exactly 
equal  in  bulk  to  the  dimensions  of  the  body  immersed.  If  a  cork 
be  rammed  hard  into  the  neck  of  a  vial  full  of  water,  the  vial  will 
burst,  while  its  neck  remains  entire.  The  disposition  of  air  to  re- 
sist penetration  may  be  illustrated  in  the  following  way :  Let  a 
tall  glass  vessel  be  nearly  filled  with  water,  on  the  surface  of 
which  a  lighted  taper  is  set  to  float ;  if,  over  this  glass,  a  smaller 
cylindrical  vessel,  likewise  of  glass,  be  inverted  and  pressed  down- 
wards, the  contained  air  maintaining  its  place,  the  internal  body 
of  the  water  will  descend,  while  the  rest  will  rise  up  at  the  sides, 
and  the  taper  will  continue  to  burn  for  some  seconds  encompassed 
by  the  whole  mass  of  liquid. 

Impetus. —  Impetus  is  the  product  of  the  mass  and  velocity  of 
a  moving  body,  considered  as  instantaneous,  as  distinguished  from 
momentum,  with  reference  to  time,  and  from  force,  with  reference 
to  capacity  of  continuing  its  motion.  Impetus  in  gunnery  is  the 
altitude  through  which  a  heavy  body  must  fall  to  acquire  a  ve- 
locity equal  to  that  with  which  the  ball  is  discharged  from  the 
piece. 

Incidence. —  The  term  incidence  in  mechanics  is  used  to  denote 
the  direction  in  which  a  body  or  ray  of  light  strikes  another 
body,  and  is  otherwise  called  inclination.  In  moving  bodies,  their 
incidence  is  said  to  be  perpendicular  or  oblique,  according  as  their 
lines  of  motion  make  a  straight  line  or  an  angle  at  the  point  of 
contact. 

Inclination. —  Inclination  denotes  the  mutual  approach  or  ten- 
dency of  two  bodies,  lines,  or  planes  towards  each  other,  so  that 
the  lines  of  their  direction  make  at  the  point  of  contact  an  angle 
of  greater  or  less  magnitude. 

The  Inclined  Plane. —  The  inclined  plane  is  the  representative 
of  the  second  class  of  mechanical  powers.  Its  fundamental  law 
of  action  is  that  of  the  composition  and  resolution  of  forces.  The 
manner  in  which  the  advantage  is  immediately  derived  from  it,  is 
therefore  distinct  from  that  of  the  first  class;  there  is  necessarily 


596         THE  engineer's  handy-book. 

a  fulcrum,  a  point  round  which  all  the  motion  takes  place,  and 
through  which  the  power  acts  on  the  resistance ;  whereas,  in  this 
class,  there  is  no  apparent  centre  of  action.  The  advantage  gained 
by  the  inclined  plane,  when  the  power  acts  in  a  parallel  direction 
to  the  plane,  is  as  the  length  to  the  height  or  angle  of  inclina- 
tion. Hence,  divide  the  weight  by  the  ratio  of  inclination,  and 
the  quotient  equals  the  power  that  will  support  that  weight  upon 
the  plane.  Or,  multiply  the  weight  by  the  height  of  the  plane 
and  divide  by  the  length  ;  the  quotient  is  the  power. 

The  descent  of  a  body  down  an  inclined  plane  is  as  the  length 
of  the  plane  to  its  height ;  so  is  the  velocity  acquired  by  a  fall- 
ing body  through  a  given  height  to  the  velocity  on  an  inclined 
plane. 

Ex. —  A  body  will  roll  down  an  inclined  plane  300  feet  long 
and  25  feet  high  in  one  second  of  time,  as  follows :  300  :  25  :  :  16  : 
1-33  =  the  distance  which  the  body  descends  per  second  on  an  in- 
inclined  plane. 

Inertia. —  Inertia  is  that  property  of  matter  by  which  it  tends, 
when  at  rest,  to  remain  so,  and,  when  in  motion,  to  continue  in 
motion. 

LgygPS^ — Levers  are  classified  into  three  different  kinds  or 
orders.  When  the  fulcrum  is  between  the  force  and  the  weight,, 
the  lever  is  called  a  lever  of  the  first  order ;  when  the  weight  is 
between  the  force  and  the  fulcrum,  the  lever  is  of  the  second 
order ;  when  the  force  is  between  the  weight  and  the  fulcrum,  the 
lever  is  of  the  third  order.  The  levers  of  safety-valves  for  steam- 
boilers  belong  to  this  last  class. 

The  lever  is  an  inflexible  bar,  by  the  application  of  which  one 
force  may  balance  or  overcome  another.  These' forces  are  termed, 
respectively,  the  power  and  the  resistance  or  weight,  not  from  any 
difference  in  the  action  of  the  forces,  but  with  reference  merely  to 
the  intention  with  which  the  machine  is  used ;  and,  indeed,  the 
same  terms  are  used  about  all  the  other  mechanical  elements.  In 
applying  the  rod  to  operate  upon  any  resistance,  it  must  rest  upon 
a  centre  prop,  or  fulcrum,  somewhere  along  its  length,  upon  which 


THE   engineer's  HANDY-BOOK. 


597 


it  turns  in  the  performance  of  its  work.  Thus,  there  are  three 
points  in  every  lever  to  be  regarded  in  examining  its  action, 
namely,  the  two  points  of  application  of  the  power,  the  weight,  and 
the  point  resting  on  the  fulcrum.  There  is  a  certain  relation  to 
be  observed  between  the  magnitudes  of  the  opposing  force  and 
tlie  distances  from  the  fulcrum,  namely,  that  in  every  case  the 
power  multiplied  by  its  distance  from  the  fulcrum  is  equal  to  the 
weight  multiplied  by  its  distance  from  the  same  point.  From  this 
relation,  simple  rules  may  be  deduced  for  calculation. 

To  know  the  power  to  be  applied,  at  a  certain  distance  from 
the  fulcrum,  to  overcome  a  resistance  acting  also  at  a  certain  dis- 
tance, multiply  the  resistance  by  its  distance  from  the  fulcrum, 
which  gives  its  momentum,  and  divide  the  product  by  the  distance 
given  ;  the  quotient  will  be  the  power,  it  being  understood  that  the 
distance  and  the  force  be  each  expressed  in  the  same  unit  of  meas- 
ure. For  example,  a  weight,  1120  lbs.,  at  3  inches  from  the  ful- 
crum, is  to  be  balanced  by  a  force  at  the  distance  of  10  feet.  Now, 
10  feet  are  equal  to  120  inches;  and  the  momentum  of  1120  lbs. 
is  1120  X  3  =  3360.  Divide  this  by  120,  we  have  28  lbs.  for  the 
power  required.  Again,  To  know  the  distance  at  which  a  given 
force  ought  to  be  applied  to  balance  a  given  weight  at  a  certain 
distance,  we  must,  in  like  manner,  multiply  the  weight  by  its  dis- 
tance, as  before,  arid  divide  by  the  given  power.  1120  lbs.,  for  ex- 
ample, at  3  inches  distance,  are  to  be  balanced  by  a  force  of  28 
lbs.  To  find  the  distance  of  this  weight,  1120  lbs.  multiplied  by 
3  gives  3360,  which,  divided  by  28,  gives  120  inches,  or  10  feet. 

Machines. —  Machines  are  instruments  employed  to  regulate 
motion,  so  as  to  save  either  time  or  force.  The  maximum  eflTect 
of  machines  is  the  greatest  eflfect  which  can  be  produced  by  them. 
In  all  machines  that  wwk  with  a  uniform  motion,  there  is  a  cer- 
tain velocity,  and  a  certain  load  of  resistance,  that  yields  the 
greatest  eflfect,  and  which  are  therefore  more  advantageous  than 
any  other.  A  machine  may  be  so  heavily  charged,  that  th^  mo- 
tion, resulting  from  the  appliration  of  any  given  power,  will  be 
but  just  sufficient  to  overcomn  it,  and,  if  any  motion  exiBue,  it 


598 


THE   engineer's  HANDY-BOOK. 


will  be  very  trifling,  and  the  whole  effect  will  be  very  slight.  If 
the  machine  is  very  lightly  loaded,  it  may  give  great  velocity  to 
the  load ;  but,  from  the  smallness  of  its  quantity,  the  effect  may 
still  be  very  inconsiderable;  consequently,  between  these  two 
loads,  there  must  be  some  intermediate  one  that  will  render  the 
effect  the  greatest  possible.  This  is  equally  true  in  the  applica- 
tion of  animal  strength,  as  in  machines.  The  maximum  effect  of 
a  machine  is  produced  when  the  weight  or  resistance  to  be  over- 
come is  four-ninths  of  that  which  the  power,  when  fully  exerted, 
is  able  to  balance,  or  of  that  resistance  which  is  necessary  to  re- 
duce the  machine  to  rest ;  and  the  velocity  of  the  part  of  the 
machine,  to  which  the  power  is  applied,  should  be  one- third  of 
the  greatest  velocity  of  the  power. 

The  moving  power  and  the  resistance  being  both  given,  if  the 
machine  be  so  constructed,  that  the  velocity  of  the  point,  to  which 
the  power  is  applied,  be  to  the  velocity  of  the  point  to  which  the 
resistance  is  applied,  as  four  times  the  resistance  to  nine  times  the 
power,  the  machine  will  work  to  the  greatest  possible  advantage. 
This  is  equally  true  when  applied  to  the  strength  of  animals; 
that  is,  a  man,  horse,  or  other  animal,  will  do  the  greatest  quantity 
of  work,  by  continued  labor,  when  his  strength  is  opposed  to  a 
resistance  equal  to  four-ninths  of  his  natural  strength,  and  his 
velocity  equal  to  one-third  of  his  greatest  velocity  when  not  im- 
peded. In  all  machines,  simple  as  well  as  compound,  what  is 
gained  in  power  is  lost  in  time ;  but  the  loss  of  time  is  compen- 
sated by  convenience.  The  power  of  a  machine  is  not  altered  by 
varying  the  size  of  the  wheels,  provided  the  proportion,  produced 
by  the  multiplication  of  the  power  of  the  several  parts,  remains 
the  same. 

Mechanics. —  Mechanics  is  that  branch  of  natural  philosophy 
which  treats  of  three  simple  physical  elements,  force,  motion,  and 
time,  with  their  combinations,  constituting  power,  space,  and 
work.  Mechanics,  regarded  as  a  science,  comprehends  the  sum 
of  our  knowledge  relative  to  the  sensible  motions  of  bodies  either 
ACtwiJly  existing,  or  expressed  by  the  opposition  of  forces  tend- 


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599 


ing  to  produce  motion.  The  science  is  thus  resolvable  into  a  code 
of  discovered  laws,  applying  to  the  causes  which  occasion  and 
modify  the  direction  and  the  velocities  of  motion,  and  is  there- 
fore distinct  from  those  branches  of  science,  in  which,  although 
presenting  phenomena  of  motion  in  sensible  portions  of  matter, 
we  do  not  consider  the  circumstances  and  laws  of  these  motions, 
but  only  the  effects  produced. 

When  motion  itself  is  considered,  the  reasoning  belongs  to 
mechanics,  and  it  is  probable  that,  as  our  knowledge  of  the  laws 
which  govern  the  phenomena  that  are  evolved  under  the  hand  of 
the  experimental  philosopher  becomes  more  extended,  a  wider 
meaning  will  be  given  to  the  science  of  motion.  The  definition 
which  is  here  given  of  mechanics  is  not  coeval  with  the  name. 
The  science,  like  most  other  sciences,  has  gradually  expanded  to 
its  present  extent.  It  was  originally  the  science  of  machines  — 
these  being  the  first  subjects  of  its  speculation ;  and,  as  every 
material  combination  employed  for  producing  or  preventing  mo- 
tion may  be  regarded  as  a  machine,  and  may  be  resolved  into  the 
same  elementary  principles  as  those  employed  in  machines, —  the 
mechanical  powers, —  the  name  "  mechanics  "  came  to  be  applied 
to  motion,  and  the  tendency  to  motion  of  any  bodies  whatever. 
Mechanics  still  continues  to  be  defined  by  some  the  "science  of 
force,"  and  there  does  not  appear  to  be  any  valid  objection  to  the 
definition.  Force  is  the  cause  of  motion,  and  its  laws  are  identi- 
cal with  the  laws  of  motion  ;  and,  consequently,  the  science  of 
force  coincides,  in  all  its  parts,  with  the  science  of  motion,  w^hich 
is  mechanics. 

All  machinery,  when  analyzed,  will  be  found  to  consist  of  a 
combination  of  six  simple  machines  or  elements,  commonly  called 
mechmiical  powers.  The  six  elements  are  respectively  the  lever, 
the  pulley,  the  ivheel  and  axle,  the  inclined  plane,  the  wedge  and 
the  screw.  Though  they  are  not  powers,  or,  in  other  words, 
sources  of  power  or  force,  yet  they  transmit  and  diflTuse  or 
concentrate  forces.  The  essential  idea  of  machinery  is,  that  it 
renders  force  available  for  eflfecting  practical  ends.  Machines 


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THE   engineer's  HANDY-BOOK. 


prepare,  as  it  were,  the  raw  material  of  force  supplied  to  us  from 
natural  sources.  It  is  transmitted  and  modified  by  certain  com- 
binations of  the  elements  of  machinery,  and  is  given  off,  at  last, 
in  a  condition  suitable  for  producing  the  desired  mechanical  ef- 
fect. We  do  not  create  force;  the  object  of  machinery  is  to 
transmit  it,  and  diffuse  or  concentrate  it  in  one  or  more  points 
of  action.  The  various  diffused  or  concentrated  forces,  then, 
being  added  together,  will  amount  exactly  to  the  original  avail- 
able force. 

Modulus. —  The  modulus  of  the  elasticity  of  any  substance  is  a 
column  of  the  same  substance,  capable  of  producing  a  pressure  on 
its  base,  which  is  to  the  weight  causing  a  certain  degree  of  com- 
pression, as  the  length  of  the  substance  is  to  the  diminution  in  its 
length. 

Momentum. —  Momentum,  in  mechanics,  is  the  same  as  impetus 
or  quantity  of  motion,  and  is  generally  estimated  by  the  product 
of  the  velocity  and  the  mass  of  the  body.  This  is  a  subject  which 
has  led  to  various  controversies  between  philosophers, —  some  esti- 
mating it  by  the  mass  into  the  velocity  as  stated  above,  while 
others  maintain  that  it  varies  as  the  mass  into  the  square  of  the 
velocity.  But  this  difference  seems  to  have  arisen  rather  from  a 
misconception  of  the  term  than  from  any  other  cause.  Those 
who  maintain  the  former  doctrine,  understand  momentum  to  sig- 
nify the  momentary  impact ;  and  the  advocates  of  the  latter  doc- 
trine recognize  it  as  the  sum  of  all  the  impulses  till  the  motion 
of  the  body  is  destroyed. 

The  momentum  of  a  body  is  the  power  contained  in  a  moving 
body,  and  is  equal  to  its  weight  multiplied  by  its  velocity. 

The  momentum  divided  by  the  velocity  equals  the  weight,  or 
the  momentum  divided  by  the  weight  equals  the  velocity. 

The  velocity  acquired  by  a  falling  body  is  proportional  to  the 
time ;  or  the  velocity  acquired  at  the  end  of  the  first  second,  mul- 
tiplied by  the  number  of  seconds,  will  be  the  velocity  with  which 
it  strikes  the  ground. 

The  space  through  which  a  body  falls  in  a  given  time  may  be 


THE   engineer's  HANDY-BOOK. 


601 


found  by  multiplying  the  square  of  seconds  by  the  distance  which 
a  body  moves  in  one  second  from  a  state  of  rest,  which  is  16 j\  feet, 
or  193  inches,  and  the  product  will  be  the  whole  space  through 
which  a  body  falls  in  a  certain  time ;  if  multiplied  in  feet,  the 
product  will  be  feet,  and  if  in  inches,  the  product  will  be  inches. 

The  space  through  which  a  body  falls  in  any  number  of  sec- 
onds may  be  calculated  as  follows :  During  the  first  second,  a  ijody 
falls  IQj^  feet;  the  second  second,  it  will  fall  3  times  IGy*^  feet; 
and  the  third  second,  5  times  16^^^  feet. 

The  distance  passed  over  by  a  body  in  an  air-tight  vessel  by 
the  force  of  gravity  is  16 ft.;  it  gradually  acquires  an  acceler- 
ated motion,  so  that  it  has  a  velocity  of  S2j\  ft.  at  the  end  of  the 
first  second. 

Ex.  —  If  a  substance  weighing  336  pounds  be  dropped  from  a 
height  of  400  feet,  its  momentum,  and  the  time  it  takes  to  reach 
the  ground,  may  be  calculated  as  follows : 

16  :  1  :  :  x/400  —  5  seconds,  the  time  of  falling. 

Now,  to  get  the  momentum,  we  must  have  the  velocity  to  mul- 
tiply into  the  weight,  and  5  seconds  being  the  time  it  was  falling, 
1  :  32  : :  5  :  160  =  velocity  in  feet  X  336  ( weight)  =  53,760  pounds 
momentum. 

Ex. —  If  a  ball  24  pounds  in  weight  be  dropped  from  a  height 
of  400  feet,  the  velocity  with  which  it  will  strike  the  ground, 
and  its  momentum,  may  be  thus  calculated.  The  time  of  falling 
must  be  first  found.  Then,  16  :  1  :  :  v/400  =  x/25  =  5  seconds 
is  the  time  of  falling.  Since  the  velocity  is  proportional  to  the 
time,  1  :  5  :  :  32  :  160,  which  is  the  velocity  in  feet  \vith  which  it 
strikes  the  ground.  Then,  as  the  momentum  is  equal  to  the  ve- 
locity multiplied  by  the  weight,  we  have  24  X  160  =  3840,  the 
momentum. 

Motion. —  Motion,  in  mechanics,  is  a  change  of  place,  or  it  is 
that  property  inherent  in  matter  by  which  it  passes  from  one 
point  of  space  to  another.  Absolute  motion  is  the  absolute 
change  of  place  in  a  moving  body,  independent  of  any  other 
motion  whatever ;  in  which  general  sense,  however,  it  never  falls 
51 


602 


THE   ENGINEER'S  HANDY-BOOK. 


under  our  observation.  All  those  motions,  which  we  consider  as 
absolute,  are  in  fact  only  relative,  being  referred  to  the  earth, 
which  is  itself  in  motion.  By  absolute  motion,  therefore,  we 
must  only  understand  that  which  is  so  with  regard  to  some  fixed 
point  upon  the  earth,  this  being  the  sense  in  which  it  is  interpreted 
by  writers  on  this  subject.  Accelerated  motion  is  that  which  is 
continually  receiving  constant  accessions  of  velocity.  Angular 
motion  is  the  motion  of  a  body  as  referred  to  a  centre,  about 
which  it  revolves.  Compound  motion  is  that  which  is  produced 
by  two  or  more  powers  acting  in  different  directions.  Natural 
motion  is  that  which  is  natural  to  bodies,  or  that  which  arises 
from  the  action  of  gravity.  Parallel  Motions. —  Contrivances 
of  this  kind  are  required  for  the  conversion  of  rotary  and  alter- 
nating angular  motion  into  rectilineal  motion,  and  the  converse; 
but  the  absolute  necessity  there  is  of  guiding  the  path  of  a  piston 
in  a  steam-engine,  has  called  forth  more  attention  to  the  principles 
and  mechanism  of  parallel  motions  than  would  otherwise,  in  all 
])robability,  have  been  awarded  to  the  subject.  Relative  motion 
is  the  relative  change  of  place  in  one  or  more  moving  bodies. 
Retarded  motion  is  that  which  suffers  continual  diminution  of 
velocity,  the  laws  of  which  are  th^  reverse  of  those  of  accelerated 
motion.  Rotary  motion,  turning  as  a  wheel  on  its  axis,  pertain- 
ing to  or  resembling  the  motion  of  a  wheel.  Rotary  motions 
were  favorite  ones  with  ancient  philoso})hers.  They  considered  a 
circle  as  the  most  perfect  of  all  figures,  and  erroneously  concluded 
that  a  body  in  motion  would  naturally  revolve  in  one. 

To  the  substitution  of  circular  for  straight  motions,  and  of 
continuous  for  alternating  ones,  may  be  attributed  nearly  all  the 
conveniences  and  elegancies  of  civilized  life.  It  is  not  too  much 
to  assert,  that  the  present  advanced  state  of  science  and  the  arts 
is  due  to  revolving  mechanism.  From  the  earliest  times  it  had 
been  an  object  to  convert,  whenever  practicable,  the  rectilinear 
and  reciprocating  movements  of  machines  into  circular  and  con- 
tinuous ones.  Old  mechanics  seem  to  have*been  led  to  this  result 
by  that  tact  or  natural  sagacity,  that  is  more  or  less  common  to 


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603 


all  times  and  people.  Thus  the  dragging  of  heavy  loads  on  the 
ground  led  to  the  adoption  of  wheels  and  rollers, —  hence  carts 
and  carriages.  The  rotary  movements  of  the  drill  superseded  the 
alternating  one  of  the  punch  and  gouge,  in  making  perforations ; 
the  whetstone  gave  way  to  the  revolving  grindstone ;  the  turning- 
lathe  produced  round  forms  infinitely  more  accurate  and  more  ex- 
peditiously than  the  uncertain  and  irregular  carving  or  cutting 
witli  the  knife.  Motion  is  uniform,  when  a  body  moves  continually 
with  the  same  velocity,  passing  over  equal  spaces  in  equal  times. 

Oscillation,  Centre  of. — The  centre  of  oscillation  is  that  point 
in  a  vibrating  body,  in  which,  if  the  whole  were  concentrated  and 
attached  to  the  same  axis  of  motion,  it  would  vibrate  in  the  same 
time  the  body  does  in  its  natural  state.  The  centre  of  oscillation 
is  situated  in  a  right  line  passing  through  the  centre  of  gravity, 
and  perpendicular  to  the  axis  of  motion. 

Pendulum. —  If  any  heavy  body,  suspended  by  an  inflexible 
rod  from  a  fixed  point,  be  drawn  aside  from  the  vertical  position, 
and  then  let  fall,  it  will  describe  the  arc  of  a  circle,  of  which 
the  point  of  suspension  is  the  centre.  On  reaching  the  vertical 
position,  it  will  have  acquired  a  velocity  equal  to  that  which  it 
would  have  acquired  by  falling  vertically  through  the  versed  sine 
of  the  arc  which  it  has  described,  in  consequence  of  which  it  will 
continue  to  move  in  the  same  arc  until  the  whole  velocity  is  de- 
stroyed ;  and,  if  no  other  force  than  gravity  were  in  operation, 
this  would  take  place,  when  the  body  reached  a  height  on  the 
opposite  side  of  the  vertical  height,  equal  to  that  from  which  it 
fell.  Having  reached  this  height,  it  would  again  descend,  and  so 
continue  to  vibrate  forever ;  but,  in  consequence  of  the  friction 
of  the  axis  and  the  resistance  of  the  air,  each  successive  vibration 
will  be  diminished,  and  the  body  soon  be  brought  to  rest  in 
the  vertical  position.  A  body  thus  suspended  and  caused  to  vi- 
brate is  called  a  pendulum  ;  and  the  passage  from  the  greatest 
distance  from  the  vertical  on  the  one  side  to  the  greatest  distance 
on  the  other  is  called  an  oscillation. 

Percussion. —  The  centre  of  percussion  is  that  point  in  a  body 


604 


THE   ENGINEER'S  HANDY-BOOK. 


revolving  about  an  axis  at  which,  if  it  struck  an  immovable  ob 
stacle,  all  its  motion  would  be  destroyed,  or  it  would  not  incline 
either  way.  When  an  oscillating  body  vibrates  with  a  given 
angular  velocity,  and  strikes  an  obstacle,  the  effect  of  the  impact 
will  be  the  greatest,  if  it  be  made  at  the  centre  of  percussion ; 
since,  in  this  case,  the  obstacle  receives  the  whole  revolving  mo- 
tion of  the  body ;  whereas,  if  the  blow  be  struck  at  any  other 
point,  a  part  of  the  motion  will  be  employed  in  endeavoring  to 
continue  the  rotation. 

Perpetual  Motion. —  In  mechanics,  a  machine  which,  when  set 
in  motion,  would  continue  to  move  forever,  or,  at  least,  until  de- 
stroyed by  the  friction  of  its  parts,  without  the  aid  of  any  exterior 
cause,  w^ould  constitute  perpetual  motion.  The  discovery  of 
perpetual  motion  has  always  been  a  celebrated  problem  in  me- 
chanics, on  which  many  ingenious,  though  in  general  ill-instructed, 
persons  have  spent  their  time ;  but  all  the  labor  bestowed  on  it 
has  proved  abortive.  In  fact,  the  impossibility  of  its  existence 
has  been  fully  demonstrated  from  the  known  laws  of  matter.  In 
speaking  of  perpetual  motion,  it  is  to  be  understood  that,  from 
among  the  forces  by  which  motion  may  be  produced,  we  are  to 
exclude  not  only  air  and  water,  but  other  natural  agents,  as  heat, 
atmospheric  changes,  etc.  The  only  admissible  agents  are  the 
inertia  of  matter,  and  its  attractive  forces,  which  may  all  be  con- 
sidered of  the  same  kind  as  gravitation.  It  is  an  admitted  prin- 
ciple in  philosophy,  that  action  and  reaction  are  equal,  and  that, 
when  motion  is  communicated  from  one  body  to  another,  the  first 
loses  just  as  much  as  is  gained  by  the  second.  But  every  moving 
body  is  continually  retarded  by  two  passive  forces, —  the  resist- 
ance of  the  air  and  friction.  In  order,  therefore,  that  motion 
may  be  continued  without  diminution,  one  of  two  things  is  neces- 
sary—  either  that  it  be  maintained  by  an  exterior  force,  (in  which 
case  it  would  cease  to  be  what  we  understand  by  a  perpetual  mo- 
tion,) or  that  the  resistance  of  the  air  and  friction  be  annihilated, 
which  is  practically  impossible. 

The  motion  cannot  be  perpetuated,  till  these  retarding  forces 


THE   ENGTNEEr\s  HANDY-BOOK. 


606 


are  compeDsated,  and  they  can  only  be  compensated  by  an  exterior 
force,  as  the  force,  communicated  to  any  body^  cannot  be  greater 
than  the  generating  force,  which  is  only  sufficient  to  continue  the 
same  quantity  of  motion,  when  there  is  no  resistance.  The  error, 
of  confounding  mere  pressure  with  energy  available  to  produce 
power,  is  the  main  origin  of  the  majority  of  attempts  at  perpetual 
motion,  and  even  sometimes  causes,  among  confused  minds,  ex- 
aggerated expectations  about  the  effects  to  be  obtained  from  me- 
chanical contrivances.  A  wound-up  spring  is  exactly  equivalent 
to  a  weight.  It  may  exert  a  certain  pressure,  great  in  proportion 
to  its  size  and  strength ;  but,  unless  it  is  allowed  to  unwind  it;  it 
cannot  produce  motion  or  power.  It  is  the  same  with  compressed 
air  or  gases ;  they  are,  in  fact,  nothing  but  wound-up  springs,  with 
this  difference,  however,  that,  in  place  of  needing  mechanical  power 
to  wind  them  up,  we  may  use  either  heat,  chemical  agencies,  or 
electricity. 

Pneumatics. — Pneumatics  is  the  science  which  treats  of  the 
mechanical  properties  of  elastic  fluids,  and  particularly  of  atmo- 
spheric air.  Elastic  fluids  are  divided  into  two  classes  —  perma- 
nent gases  and  vapors.  The  gases  cannot  be  converted  into  the 
liquid  state  by  any  known  process ;  whereas  the  vapors  are  readily 
reduced  to  the  liquid  form  by  pressure  or  diminution  of  tempera- 
ture. In  respect  to  their  mechanical  properties,  there  is,  however, 
no  essential  difference  between  the  two  classes.  Elastic  fluids,  in 
a  state  of  equilibrium,  are  subject  to  the  action  of  two  forces, 
namely,  gravity,  and  a  molecular  force  acting  from  particle  to 
particle.  Gravity  acts  on  the  gases  in  the  same  manner  as  on  all 
other  substances ;  but  the  action  of  the  molecular  forces  is  alto- 
gether different  from  that  which  takes  place  among  the  elementary 
particles  of  solids  and  liquids ;  for,  in  the  case  of  solid  bodies,  the 
molecules  strongly  attract  each  other  (whence  results  their  co- 
hesion), and,  in  the  case  of  liquids,  exert  a  feeble  or  evanescent 
attraction,  so  as  to  be  indifferent  to  internal  motion  ;  but,  in  the 
case  of  the  gases,  the  molecular  forces  are  repulsive,  and  the  mole- 
cules, yielding  to  the  action  of  these  forces,  tend  incessantly  to 
61* 


606  THE   ENGimSER's  HANDY-BOOK. 


recede  from  each  other,  and,  in  fact,  do  recede  until  their  further 
separation  is  prevented  by  an  exterior  obstacle.  Thus  air,  con- 
fined within  a  close  vessel,  exerts  a  constant  pressure  against  the 
interior  surface,  which  is  not  sensible,  only  because  it  is  balanced 
by  the  equal  pressure  of  the  atmosphere  on  the  exterior  surface. 
This  pressure  exerted  by  the  air  against  the  sides  of  a  vessel,  within 
which  it  is  confined,  is  called  its  elasticity  —  its  elastic  force  or 
tension. 

Power.  —  Power  is  the  product  of  force  and  velocity ;  that  is 
to  say,  a  force  multiplied  by  the  velocity  with  which  it  is  acting. 
The  term  horse-power  is  a  unit  of  power,  equivalent  to  a  force  of 
33,000  pounds  acting  with  a  velocity  of  one  foot  per  minute,  or 
150  pounds  acting  with  a  velocity  of  220  feet  per  minute,  which 
is  the  same  as  a  force  of  550  pounds  acting  with  a  velocity  of  one 
foot  per  second.  Man-power  is  a  unit  of  power  established  by 
Morin  to  be  equivalent  to  50  foot-pounds  of  power,  or  50  effects ; 
that  is  to  say,  a  man  turning  a  crank  with  a  force  of  50  pounds, 
with  a  velocity  of  one  foot  per  second,  is  a  standard  man-power. 

Power  implies  the  ability  to  do  so  much  work  in  a  certam  time, 
and,  like  other  things  which  we  talk  about  and  compare,  requires 
a  unit  by  which  to  measure  it.  The  unit  used  in  this  country  is 
called  a  horse-power,  and  is  equal  to  raising  33,000  lbs.  through 
a  space  of  one  foot  in  a  minute  of  time,  or  in  any  other  way  per- 
forming 33,000  foot-pounds  of  work  in  a  minute. 

Pressure. — Pressure  is  force  acting  against  some  obstacle  or 
opposing  force.  It  differs  from  weight,  inasmuch  as  pressure 
exerts  a  force  in  all  directions,  whereas  weight  exerts  its  influ- 
ence only  in  one.  There  are  instances  where  weight  causes  press- 
ure in  more  than  one  direction,  e,  g,,  in  fluids,  while  there  are 
others  in  which  pressure  has  no  connection  with  weight,  such  as 
the  pressure  of  steam  in  a  boiler. 

Prime  Movers. — Prime  movers  are  those  machines  from  which 
we  obtain  power  through  their  adaptation  to  the  transformation 
of  some  available  natural  force  into  that  kind  of  efibrt  which  de- 
velops mechanical  power. 


THE    ENGINEER\s    HANDY-BOOK.  607 

The  Pulley. — Pulleys  are  of  two  kinda,  fixed  and  movable.  The 
fixed  pulley  only  turns  upon  its  axis,  and  affords  no  mechanical 
advantage;  therefore,  when  the  power  and  the  weight  are  equal, 
[  they  balance  each  other.    It  is  used  for  the  convenience  of  chang- 
:   ing  the  direction  of  a  motion.    The  movable  pulley  not  only  turns 
J   upon  its  axis,  but  rises  and  falls  with  its  weight.    Every  movable 

I pulley  may  be  considered  as  hanging  by  two  ropes  equally  stretched, 
and  which,  consequently,  are  equal  portions  of  the  weight ;  there- 
fore each  pulley  of  this  sort  doubles  the  power.  The  principle  of 
the  pulley,  as  practically  applied  in  the  block  and  tackle,  is  the 
distribution  of  weight  on  various  points  of  support,  the  mechani- 
cal advantage  derived  depending  entirely  upon  the  flexibility  and 
tension  of  the  rope  and  the  number  of  pulleys  or  sheaves  in  the 
lower  or  rising  block.  Hence,  by  blocks  and  tackle  of  the  usual 
kind,  the  power  is  to  the  weight  as  the  number  of  cords  attached 
to  the  lower  block.  The  advantages  to  be  gained  by  the  employ- 
ment of  the  block  and  tackle  may  be  found  by  dividing  the  weight 
to  be  raised  by  the  number  of  cords  leading  to,  from,  or  attached 
to  the  lower  block,  and  the  quotient  is  the  power  required  to  pro- 
duce an  equilibrium,  provided  friction  does  not  exist.  Or,  divide 
the  weight  to  be  raised  by  the  power  to  be  applied  ;  the  quotient 
is  the  number  of  sheaves  in,  or  cords  attached  to,  the  rising  block. 

The  Screw. — The  screw  is  another  modification  of  the  inclined 
plane,  and  it  may  be  said  to  remove  the  same  kind  of  practical 
inconveniences  incidental  to  the  use  of  the  latter,  that  the  pulley 
does  in  reference  to  the  simple  lever.  The  lever  is  very  limited 
in  the  extent  of  its  action ;  so  is  the  inclined  plane.  But  the  pul- 
ley multiplies  the  extent  of  the  action  of  the  lever,  by  presenting^ 
in  effect,  a  series  of  levers  acting  in  regular  succession  ;  and  just 
such  a  purpose  is  effected  by  the  screw.  It  multiplies  the  extent 
of  the  action  of  the  inclined  plane  by  presenting,  in  effect,  a  con- 
tinued series  of  planes. 

The  screWj  in  principle,  is  that  of  an  inclined  plane  wound 
round  a  cylinder,  which  generates  a  spiral  of  uniform  inclination, 
each  revolution  producing  a  rise  or  traverse  motion  equal  to  the 


608 


THE   ENGINEER'S  HANDY-BOOK. 


pitch  of  the  screw  or  distance  between  the  two  consecutive  threads, 
the  pitch  being  the  height  or  angle  of  inclination,  and  the  circum- 
ference the  length  of  the  plane.  Hence,  the  mechanical  advan- 
tage is  as  the  circumference  of  the  circle  described  by  the  lever 
where  the  power  acts  is  to  the  pitch  of  the  screw,  so  is  the  force 
to  the  resistance  in  principle. 

To  find  the  effective  power  obtained  by  a  screw  of  J-inch  pitch, 
and  moved  by  a  force  equal  to  50  lbs.  at  the  extremity  of  a  lever 
30  inches  in  length : 

875 

To  find  the  power  necessary  to  overcome  a  resistance  equal  to 
7000  lbs.  by  a  screw  of  l|-inch  pitch,  and  moved  by  a  lever  25 
inches  in  length : 

7000x1-25  ..-^ 

  z=z  55*73  lbs. 

25  X  2  X  31416 

In  the  case  of  a  screw  acting  upon  the  periphery  of  a  toothed 
wheel,  the  power  is  to  the  resistance  as  the  product  of  the  circle's 
circumference  described  by  the  winch  or  lever  and  radius  of  the 
wheel  to  the  product  of  the  screw's  pitch  and  radius  of  the  axle, 
or  point  whence  the  power  is  transmitted ;  but  observe  that,  if  the 
screw  consist  of  more  than  one  thread,  the  apparent  pitch  must 
be  increased  so  many  times  as  there  are  threads  in  the  screw. 
Hence,  to  find  what  weight  a  given  power  will  equipoise,  multiply 
together  the  radius  of  the  wheel,  the  length  of  the  lever  at  which 
the  power  acts,  the  magnitude  of  the  power,  and  the  constant 
number  6*2832 ;  divide  the  product  by  the  radius  of  the  axle  into 
the  pitch  of  the  screw,  and  the  quotient  is  the  weight  that  the 
power  is  equal  to. 

Resilience  is  a  characteristic  of  bodies,  which  manifests  a  cer- 
tain degree  of  flexibility  before  they  can  be  broken,  hence  the 
body  that  bends  or  yields  the  most  at  the  time  of  fracture  is  the 
toughest. 

Statics  is  the  science  of  forces  in  equilibrium.  It  treats  of  the 
strength  of  materials,  of  bridges,  and  of  girders ;  the  stability  of 


THE   ENGINEER'S  HANDY-BOOK. 


609 


walls,  steeples,  and  towers ;  the  static  momentum  of  levers,  with 
their  combinations  into  weighing-scales,  windlasses,  pulleys,  fu- 
nicular machines,  inclined  planes,  screws,  catenaria,  and  all  kinds 
of  gearing. 

Strength. — Strength  is  the  resistance  which  a  body  opposes  to 
a  disintegration  or  separation  of  its  parts.  Tensile  strength  is  the 
absolute  resistance  which  a  body  makes  to  being  torn  apart  by 
two  forces  acting  in  opposite  directions.  Crushing  strength  is  the 
resistance  which  a  body  opposes  to  being  battered  or  flattened 
down  by  any  weight  placed  upon  it.  Transverse  strength  is  the 
resistance  to  bending,  or  flexure,  as  it  is  called.  Torsional  strength 
is  the  resistance  which  a  body  oflers  to  any  external  force  which 
attempts  to  twist  it  round.  Detrusive  strength  is  the  resistance 
which  a  body  oflers  to  being  clipped  or  shorn  into  two  parts  by 
such  instruments  as  shears  or  scissors.  TForKn^ strength.  The 
term  "working  strength"  implies  a  certain  reduction  made  in  the 
estimate  of  the  strength  of  materials,  so  that,  when  the  instrument 
or  machine  is  put  to  use,  it  may  be  capable  of  resisting  a  greater 
strain  than  it  is  expected  on  the  average  to  sustain. 

Tools. — By  the  term  tools,  according  to  the  definition  given 
by  Rennie,  we  understand  instruments  employed  in  the  manual 
arts  for  facilitating  mechanical  operations,  by  means  of  percus- 
sion, penetration,  separation,  and  abrasion,  of  the  substances 
operated  upon,  and  for  all  ^vhich  operations  various  motions  are 
required  to  be  imparted  either  to  the  tool  or  to  the  work. 

Torsion.  —  Torsion,  in  mechanics,  is  the  twisting  or  wrenching 
of  a  body  by  the  exertion  of  a  lateral  force.  If  a  slender  rod  of 
metal,  suspended  vertically,  and  having  its  upper  end  fixed,  be 
twisted  through  a  certain  angle  by  a  force  acting  in  a  plane  per- 
pendicular to  its  axis,  it  will,  on  the*  removal  of  the  force,  untwist 
itself,  or  return  in  the  opposite  direction  with  a  greater  or  less 
velocity,  and,  after  a  series  of  oscillations,  will  come  to  rest  in  its 
original  position.  The  limits  of  torsion,  within  which  the  body 
will  return  to  its  original  state,  depend  on  its  elasticity.  A  fine 
wire  of  a  few  feet  in  length  may  be  twisted  through  several  revo- 

20 


610 


THE    engineer's  HANDY-BOOK. 


lutions,  without  impairing  its  elasticity  ;  and,  within  those  limita. 
the  force  evolved  is  found  to  be  perfectly  regular,  and  direct)y 
proportional  to  the  angular  displacement  from  the  position  of  rest 
If  the  angular  displacement  exceeds  a  certain  limit  (as  in  a  wire 
of  lead,  for  example,  before  disruption  takes  place),  the  particles 
will  assume  a  new  arrangement,  or  take  a  set,  and  will  not  return 
to  their  original  position  on  the  withdrawal  of  the  disturbing  force. 

Velocity. — Velocity  is  the  rate  of  motion.  Velocity  is  inde- 
pendent of  space  and  time,  but,  in  order  to  obtain  its  value  or 
expression  as  a  quantity,  we  compare  space  with  time.  Thus, 
when  the  value  of  the  velocity  of  a  moving  body  is  required,  we 
measure  the  space  which  the  body  passes  through,  and  divide 
that  space  by  the  time  of  passage,  and  the  quotient  is  the  velocity. 

Weight. — The  weight  of  a  body  is  the  force  of  attraction  be- 
tween the  earth  and  that  body.  The  weight  of  a  body  is  greatest 
at  the  surface  of  the  earth,  and  decreases  above  or  below  that 
surface.  Above  the  surface,  the  weight  decreases  as  the  square 
of  its  distance  from  the  centre  of  the  earth,  and  belov/  the  surface 
the  weight  decreases  simply  as  its  distance  from  the  centre. 

Weights  and  Measures.  —  The  weiglits  and  measures  of  this 
country  are  identical  with  those  of  England.  In  both  countries 
they  repose,  in  fact,  upon  actually  existing  masses  of  metal  (brass), 
which  have  been  individually  declared  by  law  to  be  the  units  of 
the  system.  In  scientific  theory,  they  are  supposed  to  rest  upon  a 
permanent  and  universal  law  of  nature  —  the  gravitation  of  dis- 
tilled water  at  a  certain  temperature  and  under  a  certain  atmos- 
pheric pressure.  In  this  aspect,  the  origination  is  with  the  grains, 
which  must  be  such  that  252,458  of  these  units  of  brass  will  be 
in  just  equilibrium  with  a  cubic  inch  of  distilled  water,  when  the 
mercury  stands  at  30  inches  in  a  barometer,  and  at  62  degrees  in 
a  thermometer  of  Fah.  Unfortunately,  the  expounders  of  this 
theory  in  England  used  only  the  generic  term  brass,  and  failed  to 
define  the  specific  gravity  of  the  metal  to  be  employed ;  the  con- 
sequence of  this  omission  is  to  leave  room  for  an  error  of  jq^^q-q 
in  every  attempt  to  reproduce  or  compare  the  results.    This  is  the 


THE    engineer's  HANDY-BOOK. 


611 


minimum  possible  error;  the  maximum  would  be  a  fraction  of  the 
difference  in  specific  gravity  between  the  heaviest  and  lightest 
brass  that  can  be  cast. 

The  Wheel  and  Axle. — The  wheel  and  axle  may  be  considered 
as  a  perpetual  lever,  from  the  constant  renewal  of  the  points  of 
suspension  and  resistance.  The  fulcrSm  is  the  centre  of  the  axis, 
the  longer  arm  is  the  radius  of  the  wheel,  and  the  shorter  arm  the 
radius  of  the  axis.  As  the  diameters  of  different  circles  bear  the 
same  proportion  to  each  other  that  their  respective  circumferences 
do,  the  power  is  also  to  the  weight  as  the  diameter  of  the  wheel  is 
to  the  diameter  of  the  axle.  If  one  wheel  move  another  of  equal 
circumference,  no  power  will  be  gained,  as  they  will  both  move 
equally  fast.  But  if  one  wheel  move  another  of  different  diameter, 
whether  larger  or  smaller,  the  velocities  with  which  they  move  will 
be  inversely  as  their  diameters,  circumferences,  or  number  of  teeth. 

The  Wedge. — The  wedge  is  a  double  inclined  plane,  conse- 
quently its  principles  are  the  same.  Hence,  when  two  bodies  are 
forced  asunder,  by  means  of  the  wedge,  in  a  direction  parallel  to 
its  head,  multiply  the  resisting  power  by  half  the  thickness  of  the 
head  or  back  of  the  wedge,  and  divide  the  product  by  the  length 
of  one  of  its  inclined  sides ;  the  quotient  is  the  force  equal  to  the 
resistance.  The  breadth  of  the  back  or  head  of  a  wedge  being  3 
inches,  its  inclined  sides  each  10  inches,  required  the  power  neces- 
sary to  act  upon  the  wedge  so  as  to  separate  two  substances  whose 

resisting  force  is  equal  to  150  lbs.  ^^^^  ^  ^  —  22*5  lbs. 

Work  is  a  term  in  mechanics  of  recent  origin,  but  of  grea\ 
utility;  it  means  a  compound  of  force,  pressure,  and  motion. 
Work  is  said  to  be  performed  w^hen  a  pressure  is  exerted  upon  a 
body,  and  the  body  is  thereby  moved  through  space.  The  unit 
of  pressure  is  a  pound,  the  unit  of  space  a  foot;  and  work  is 
measured  by  a  foot-pound  as  a  unit.  Thus,  if  a  pressure  of  so 
many  pounds  be  exerted  through  a  space  of  so  many  feet,  the 
number  of  pounds  is  multiplied  into  the  number  of  feet,  and  th^ 
product  is  the  number  of  foot-pounds  of  work. 


612 


THE   engineer's  HANDY-BOOK. 


Metals  and  Alloys. 
TABLE 

OF  MINERAL  SUBSTANCES  AND  THEIR  CHEMICAL  EQUIVALENTS. 


Names. 


Aluminium  

Antimony  

Arsenic  

Barium  

Beryllium,  or) 

Glucinium  j 

Bismuth  

Boron  

Bromine  

Cadmium  

Caesium  

Calcium  

Carbon  

Cerium  

Chlorine  

Chromium  

Cobalt...  

Columbium,  ) 

or  Niobium  j 

Copper  

Didymium  

Erbium   

Fluorine  

Gallium  

Glucinium,or\ 

Beryllium../ 

Gold  

Hydrogen  

Indium  

Iodine  

Iridium  

Iron  

Lanthamum ... 

Lead  

Lithium  

Magnesium  


New  At  omic 
Weights. 


27-4 
122-0 

750 
137-0 

9-0 

209-0 
10-9 
80-0 
112-0 
183-0 
40-0 
12-0 
92-0 
35-5 
52-5 
59-0 

94-0 

63-4 
96-0 
112-6 
19-0 


9-0 

196-  0 
2-0 

114-0 
127-0 

197-  2 
56-0 

139-0 
207-0 
7-0 
24-3 


Old  Atomic 
Weights. 


13-7 
122-0 
75-0 
68-5 

4-5 

209-0 
10-9 
80-0 
56-0 

133-0 
20-0 
6-0 
46-0 
35-5 
26-25 
29-5 

94-0 

31-7 
48-0 


19-0 

4-5 

98-0 
1-0 
57-0 

127-0 
98-6 
28-0 
69-5 

103-5 
7-0 
12-15 


Names. 


Manganese.... 

Mercury  

Molybdenum 

Nickel  

Niobium,  or\ 
Columbiumj 
Nitrogen .. 

Osmium  

Oxygen  

Palladium... 

Phosphorus  

Platinum. ... 
Potassium... 
Rhodium..... 
Rubidium ... 
Ruthenium.. 

Selenium  

Silicon  

Silver  

Sodium  

Strontium  ... 

Sulphur  

Tantalum.... 
Tellurium... 

Terbium  

Thallium... 

Thorium  

Tin  

Titanium  

Tungsten  — 

Uranium  

Vanadium... 

Yttrium  

Zinc  

Zirconium... 


New  Atomic 
Weights. 


55-0 
200-0 
96-0 
59-0 

94-0 

14-0 
199-0 

16-0 
106-5 

31-  0 
197-4 

39-11 
104-0 
85-5 
104-0 
79-5 
28-0 
108-0 
23-0- 
87-5 

32-  0 
182-0 
129-0 
148-5 
204-0 
231-0 
118-0 

50-  0 
184-0 
120-0 

51-  0 
92-5 
65-0 
89-5 


Iron  is  the  most  important  of  all  the  metals  known  to  man^  as 
well  as  the  most  useful.    It  has  been  one  of  the  principal  agents 


THE   ENGINEER'S  HANDY-BOOK. 


613 


in  the  civilization  of  the  human  race,  and  is  at  the  present  day 
more  extensively  employed  in  the  mechanical  arts  than  any  other 
metal.  It  is  found  in  different  conditions,  but  always  in  the  state 
of  oxides,  or  as  iron  ore,  that  is,  a  sort  of  rusty  metallic  state.  The 
most  common  kind  —  the  hematite  or  blood-stone  —  may  be  de- 
scribed as  iron-rust  solidified,  or  rendered  concrete  by  water.  After 
being  taken  from  the  ground  in  the  condition  of  ore,  it  is  placed 
in  a  blast-furnace  and  smelted,  after  which  it  is  rendered  fibroua 
and  ductile  by  puddling.  Spiegel  iron  or  specular  cast-iron  is,  as 
its  name  implies,  largely  crystalline,  presenting  bright,  mirror-like^ 
cleavage  planes. 

Wrought-ipon  varies  in  specific  gravity  from  7  8  to  7*6 ;  taking 
the  mean  at  7*7,  a  cubic  foot  will  weigh  479-8721664  lbs.,  or  nearly 
480  lbs.  Cast-iron  varies  in  specific  gravity  from  7*5  to  6*9,  the 
average  being  7*2. 


Wrought-Iron,  Lbs. 

Cast-iron,  Lbs. 

A  cylindrical  inch  

479-872 
376-891 
251-261 
0-2777 
0-2181 
0-1454 

439-800 
344-407 
230-279 
0-2845 
0-1999 
0-1333 

Cast-iron  is  composed  of  about  91  per  cent,  of  iron,  5  of  car- 
bon, 2  of  silicon,  and  2  parts  of  sulphur  phosphorus,  and  other 
impurities.  It  also  contains  manganese,  nickel,  cobalt,  chromium, 
vanadium,  titanium,  and  tungsten,  in  minute  quantities.  The 
parts  of  steam-engines  generally  made  of  wrought-iron  are  the 
link,  eccentric-rods  and  straps,  valve-  and  piston-rods,  connecting- 
rods,  air-pump  levers,  cross-heads  for  pumps,  arms,  etc. 

Rust.' — The  red  powder  that  falls  from  iron  which  has  long 
been  subjected  to  the  action  of  moisture,  is  the  oxide  of  the  metal, 
and  is  termed  rust. 

Steel  is  one  of  the  chemical  modifications  of  iron,  a  combina- 
tion of  iron  and  carbon.  It  is  composed  of  98*6  of  iron  and  1*4 
52 


614 


THE   ENGINEER'S  HANDY-BOOK, 


of  carbon.  The  steel  containing  the  least  carbon  is  the  softest, 
and  that  containing  the  most  is  the  hardest. 

Cast-iron,  wrought-iron,  and  steel  can  be  distinguished  from 
each  other  by  the  difference  in  the  grain  —  wrought-iron  being  finer 
in  the  grain  than  cast,  and  steel  finer  than  wrought;  cast-iron  be- 
ing short  and  brittle,  wrought-iron  fibrous,  and  steel  void  of  fibre. 

Steel  and  cast-iron  are  fusible;  wrought-iron  is  malleable, duc- 
tile, tough,  fibrous,  and  possesses  the  quality  of  welding;  steel, 
also,  is  capable  of  being  welded.  From  this  it  will  be  seen,  that 
steel  possesses  properties  in  common  with  both  wrought-  and  cast- 
iron.  Malleable  iron  is  composed  of  99*5  per  cent,  of  iron,  0*035 
of  carbon,  0*076  of  silicon,  and  the  rest  is  sulphur  and  phos- 
phorus. Its  principal  value  consists  in  its  property  of  resisting 
the  chemical  action  of  salt  water  or  steam. 


showing  the  heat-conducting  properties  of  r)ifferent  metals. 

Conductive  Property 
FOR  Transmission  of 


Copper   1000. 

Brass   468. 

Wrought-iron     ......  336. 

Cast-iron  311. 

From  the  above,  it  is  evident  that  copper  possesses  the  highest 
conducting  properties. 


showing  the  tenacity  or  tensile  strength  of  different  metals. 

.Tenacity  in  Lbs. 
PER  Square  Inch. 


TABLE 


Heat. 


TABLE 


Gun-Metal  (cast) 
Iron,  Wrought  . 
Iron,  Cast  . 


Copper  (cast) 
Brass  (cast) 


.  51,000  to  61,000. 

20,000. 


19,000. 
18,000. 
36,000. 


THE   ENGINEER\s  HANDY-BOOK. 


615 


Brass  or  gun-metal  is  used  for  nuiin-hearings  of  marine-engines 
and  propeller-shafts,  link-blocks,  air-pump  buckets,  head-  and  foot- 
valves,  stern-tube  bushes,  propellers,  and  steam-  and  water-cocks. 
White  metal  is  frequently  used  as  a  lining  for  main  propeller- 
shaft  and  tunnel-bearings.  Its  chief  value  consists  in  its  anti- 
friction and  lubricating  properties,  while  its  disadvantages  are 
that,  if  it  becomes  overheated,  it  will  melt  and  run  out  of  the 
bearing.  Muntz  metal  is  used  for  surface-condenser  tubes,  air- 
and  circulating-pump  rods,  and  surface-condenser  tube-plates.  It 
is  malleable,  has  a  high  tensile  strength,  is  very  durable,  and  not 
liable  to  corrosion. 

TABLE 

SHOWING  THE  PROPORTION  OF  CARBON   IN  THE  VARIOUS  GRADES  OP 
IRON  AND  STEEL. 

Iron  semi-steelified  contains     .       .       .  1-150  of  Carbon. 

Soft  Steel  capable  of  welding  .       .       .  1-120  " 

Cast  steel  for  common  purposes       .  •     .  1-100  " 

Cast  steel  requiring  more  hardness  .       .  1-90  " 
Steel  capable  of  standing  a  few  blows, 

but  quite  unfit  for  drawing  .       .       .  1-50  " 
First  approach  to  a  steely,  granulated 

fracture  1-40  ** 

White  cast-iron  1-25  " 

Mottled  cast-iron  1  -20 

Carbonated  cast-iron        .       .       .       .  1-15  " 

Super-carbonated  crude  iron     .       .       .  1-12  " 

Copper  is  softer  and  more  ductile  than  iron,  is  easily  melted, 
and,  when  cast,  is  almost  always  free  from  blisters  and  sound 
Its  chief  drawback  is  its  cost  and  great  w'eight,  which  are  nearly 
double  that  of  iron.  Its  superior  conducting  pOwer  is  to  some 
extent  offset  by  the  greater  thickness  required  for  strength. 

Sulphur  is  less  influenced  by  changes  of  temperature  than  any 
known  mineral.  It  has  a  strong  affinity  for  iron,  and,  as  there  is 
a  great  deal  of  it  in  bituminous  coal,  the  sulphuretted  hydrogen 
gas,  disengaged  from  the  fuel,  attacks  and  soon  destroys  the  metal 


616 


THE   ENGINEER'S  HANDY-BOOK. 


Babbitt's  Metal.  —  Its  composition  is  as  follows:  Four  pounds 
of  copper,  eight  pounds  of  regulus  of  antimony,  and  eighty-eight 
pounds  of  tin.  The  copper  is  first  melted ;  the  tin  and  the  regu- 
lus of  antimony  are  then  added.  After  the  metals  have  been 
fused  a  short  time,  and  brought  to  a  dull  red  heat,  it  is  fit  for  use. 

Another  durable  alloy  for  the  journal-boxes  of  steam-engines,  is 
copper,  84 ;  zinc,  8 ;  tin,  2 ;  lead,  4 ;  and  iron,  5  parts. 

Bronze  Alloy.  —  Copper,  80  ;  tin,  18;  zinc,  2.  If,  after  cast- 
ing, and  while  still  red  hot,  cold  water  is  poured  over  it,  it  becomes 
liarder,  and  finer  in  grain,  and  tougher,  as  the  tin,  instead  of  sepa- 
rating, as  happens,  when  the  bronze  cools  slowly,  remains  mixed, 
and  the  alloy  retains  its  compactness. 


Alloys  and  Compositions. 


Brass  for  locomotive  bearings.... 

Brass  for  glands  

Brass  engine  bearings  

Yellow  brass  for  turning  

Brass  richer  

Box  metal  

Red  brass  

Flanges  to  stand  brazing  

Tough  brass  engine  work  

Tough  brass  for  heavy  bearings. 

Mimtz  metal  

White  metal....  

White  metal,  hard.  

Bronze  red  

Bronze  yellow  

Gun  metal  for  bearings  

Bell  metal  for  large  bells  

Britannia  metal  

Brass  for  sheets  

Nickel-silver,  English  

Nickel-silver,  Parisian  

German  silver  


50' 

65- 

50- 

40- 

SO- 
SO- 

70- 

64- 
100- 
160- 

90- 

11- 
104-7 
130-5 
100-8 

90-3 

80- 
1- 

84-7 

60- 

66- 

50- 


2-5 

0-  5 

1-  8 
20- 
10- 
10- 
10- 

2- 
15- 

5- 
60- 
11- 
38-7 
19-5 
46-8 

9-67 


2-' 

15-3 
17-8 
13-6 
25' 


5- 
8- 
6-5 


15- 
25- 

42-6 


2-4 
0-3 

20- 

81- 


85-2 


16' 


22-2 

19- 

25- 


THE    ENGINEER'S  HANDY-BOOK. 


617 


Solder. 

Silver  solder  is  generally  composed  of  4  parts  silver  and  2 
parts  yellow  brass.  Pure  copper,  in  thin  strips,  is  generally  used 
for  soldering-irons.  Plumbers'  solder  is  composed  of  2  parts  tin 
and  4  parts  lead.  This  solder  melts  at  about  450^  Fah.  Tin- 
smiths' solder  is  composed  of  4  parts  tin  and  2  parts  lead.  This 
solder  melts  at  about  350°  Fah.  Bismuth  solder  is  composed 
of  7  parts  bismuth,  5  parts  lead,  and  3  parts  tin.  This  solder  melts 
at  about  225°  Fah.  All  tin  and  lead  solders  become  more  fusible 
the  more  tin  they  contain.  Thus,  1  part  tin  and  10  parts  lead 
melt  at  about  550°  Fah. ;  while  6  parts  tin  and  1  part  lead  melt 
at  about  375°  Fah.  All  the  tin,  lead,  and  bismuth  solders  become 
more  fusible  the  more  lead  and  bismuth  they  contain. 


TABLE 

SHOWING  THE  AVERAGE  CRUSHING  LOAD  OF  DIFFERENT  MATERIALS, 
OR  THE  W^EIGHT  UNDER  WHICH  THEY  W^ILL  CRUMBLE. 


Lbs.  per  Sq.  Inch. 

Lb.<!. 

per  Sq.  Inch. 

Alder  

6,900 

Walnut     .    .  . 

.    .  6,000 

Ash  

8,600 

Willow     .    .  . 

.    .  2,900 

Beech  

7,600 

Oast  iron.  Am. 

.    .  174.803 

5,700 

Low  moor,  Eng  . 

.    .  62,450 

Elm  ...... 

10,000 

Wrought-iron 

.    .  38,000 

Fir  —  Spruce     .  . 

.  6,500 

Steel,  cast  .    .  . 

.    .  225,000 

Hickory  (white)  .  . 

.  8,925 

"     tempered  . 

.    .  337.800 

Hornbeam     .    .  . 

.  4,500 

Copper,  cast  .  . 

.  .117,000 

3,200 

Brass,     "     .  . 

.    .  164,800 

9,113 

Tin,        "     .  . 

.    .  15,500 

8,150 

Lead  .... 

.    .  7,730 

Oak  

4,200 

Hard  brick    .  . 

.    .  2,000 

"   English  .    .  . 

.  6,500 

Crown  glass   .  . 

.    .  31,000 

Pine  (pitch)  .    .  . 

.  6,800 

Granite,  Eng. .  . 

.    .  10,360 

"   Am.  yellow 

.  5,300 

Portland  cement 

.    .  15,000 

,  5,100 

Freestone,  Conn. 

.    .  3,522 

Plum  

.  3,700 

Marble,  Am.  .  . 

.    .  18,061 

.  7,000 

Roman  cement  . 

.    .  342 

Teak  

,  12,000 

618 


THE   engineer's  HANDY-BOOK. 


TABLE 

SHOWING   THE   TENSILE  STRENGTH,  OR  THE   STRAIN   THAT  WILL  PULL 
DIFFERENT  METALS  ASUNDER  ON  A  STRAIGHT  PULL. 


Ll)s.  p6r 

Sq.  Inch. 

Antimony    .       .       .  . 

1,000 

Bismuth      .       .       .  . 

3,200 

Brass  —  cast 

18,000 

Copper  —  cast 

19,000 

Gun-metal,  copper,  and  tin  . 

96,000 

Iron  —  cast  .       .       .  . 

17,900 

Wrought-iron  —  bar 

57,500 

  good    .       .       .  . 

60,000 

 superior 

70,000 

 best  American 

76,160 

 low  moor 

60,000 

 boiler-plate  . 

45,000 

 rivet — English  . 

65,000 

Steel  plates  —  English  . 

78,000 

Lbs.  per 
Sq.  Jnch. 

Steel  plates — Hussey,  Wells 


&  Co. — American    .  94,450 

 Bessemer — American  98,600 

Bessemer  steel  —  tool  .  .  112,000 
Steel,  bar — Black  Diamond 

—American    .       .  120,700 

 tempered    .       .       .  214,400 

Chrome  steel — American  .  180,000 

Silver— cast       .       .       .  41,000 

Tin  — block       .       .       .  4,600 

Zinc  — cast  ....  2,800 

"      sheet       .       .       .  16,000 

wire        .       .       .  22,000 


TABLE 


SHOWING  THE  TENSILE  STRENGTH  OF  DIFFERENT  KINDS  OF  WOOD. 


Lbs.  iter 
Sq.  Inch. 

Alder  . 

.  14,000 

Hickory 

Ash 

.  16,000 

Lignum-Vitse 

Birch  . 

.  15,000 

Larch  . 

Bay  wood 

.  12,000 

Locust  . 

Beech  . 

.  11,500 

Maple  . 

Bamboo 

.  6,000 

Mahogany 

Boxwood 

.  20,000 

Oak  . 

Cedar  . 

.  7,000 

Pear 

Chestnut 

.  13,00? 

Pine 

Cypress  . 

.  6,000 

Poplar  . 

Elder  . 

.  10,000 

Sycamore 

Elm 

.  6,000 

Teak  . 

Fir  or  Spruce 

.  10,000 

Walnut . 

Hazel  . 

.  18,000 

Yew  . 

Holly  . 

.  16,000 

THE  engineer's  iiandy-book.  619 

Black  Finish  for  Brass. —  Make  a  strong  solution  of  nitrate  of 
silver  in  one  dish  and  nitrate  of  copper  in  another.  Mix  the  two 
together  and  plunge  the  brass  into  it.  Now  heat  the  brass 
evenly  until  the  required  degree  of  dead  blackness  is  obtained. 
This  is  the  method  used  by  French  instrument-makers  to  pro- 

,  duce  the  beautiful  dead-black  color  so  much  admired  in  optical 

i  instruments. 

Lacquer  for  Brass  Castings. — Tak^  of  shellac,  6  oz. ;  amber 
of  copal,  ground,  2  oz. ;  dragon's  blood,  40  grains ;  extract  of  r^d 
sandal- wood,  30  grains;  oriental  saffron,  36  grains;  pounded  glass, 
4  oz. ;  very  pure  alcohol,  44  oz.  To  apply  to  brass,  expose  to  a 
gentle  heat  and  dip  them  in. 

Solder. — The  following  solder  will  braze  steel  or  iron,  and  may 
be  found  very  useful  in  case  of  a  valve-stem  or  other  light  portion 
of  an  engine  or  machine  breaking  at  a  time  when  it  is  important 
that  the  engine  or  machine  should  continue  work :  Silver,  19 
parts ;  copper,  1  part ;  brass,  2  parts. 

Fusible  Metal,  consisting  of  8  parts  of  bismuth,  5  of  lead,  and 
3  of  tin.  It  melts  at  the  heat  of  boiling  water,  or  212°  Fah.  By 
the  addition  of  a  very  little  mercury,  it  becomes  still  more  fusible, 
and  is  used  for  certain  anatomical  injections  and  for  the  filling  of 
carious  teeth. 

Rule /or  finding  the  approximate  weight  of  iron  castings  from  pat- 
terns,—  Multiply  the  weight  of  the  pattern  by  the  figures  corre- 
sponding to  the  material  in  the  table.    Very  accurate  results  can- 
not be  expected,  as  the  specific  gravity  of  wood  as  well  as  of  iron ' 
varies. 


Pine  wood  ........  14*0 

Oak  9-0 

Beech  "  9*7 

Linden"  .       .     ^.       .       .       .       .       .  134 

Birch    "  .       .  .       .       .       .       .  10-6 

Alder  "  12*6 

Pear-tree  wood  10  0 


620 


THE   ENGINEER'S  HANDY-BOOK. 


TABLE 

SHOWING  THE  WEIGHT  OF  CASTINGS  BY  WEIGHT  OF  THE  PATTERNS. 

Multiply  the  weight  of  the  pattern  by  the  multiplier  opposite 
each  material. 


White  Piue  X  16 

X  17-1 

X  17-3 

X  18 

X  25 


Cast-iron. 

Wrought-iron. 

Steel. 

Copper. 

Lead. 


TABLE 

SHOWING  THE  SHRINKAGE  OF  CASTINGS  OF  DIFFERENT  METALS. 


Cast-iron,  ^  inch  per  lineal  foot. 
Brass,  j\ 
Lead,  i 


Tin,  inch  per  lineal  foot. 
Zinc, 


TABLE 


SHOWING  THE  WEIGHT  AND  BULK  OF  DIFFERENT  SUBSTANCES  IN  CUBIC 
FEET,  POUNDS  AND  TONS. 


0.2  0  . 

CO  0 

00 

0.2  0  . 

Names  of  Substances. 

Names  of  Substances. 

0 

5 
0 

Cast-iron  .    »    .  . 

450-5 

4-97 

Oak,  white  .    .  . 

45-2 

49-5 

Wroiight-iron  .  . 

486-6 

4-60 

Clay  

101-3 

22-1 

Steel   

489-8 

4-57 

Concrete,  ordinary 

115-0 

19-5 

Copper  .... 

5550 

4-03 

Brick  

100-0 

22-4 

Lead  

707-0 

3-16 

Plaster,  Paris   .  . 

105-0 

21-3 

537-7 

4-16 

Sand  

94-5 

23-7 

Tin  

456-0 

4-91 

Granite  .... 

139-0 

161 

Pine,  white  .    .  . 

29-56 

75-6 

Earth,  loose .    .  . 

78-6 

28-5 

"    yellow     .  . 

33-81 

66-2 

Water,  salt  (sea)  . 

64-3 

34-8 

Mahogany    .    .  . 

66-4 

33-8 

Water,  fresh     .  . 

62-5 

35-9 

Marble,  common  . 

141-0 

15-9 

58-08 

38-56 

Millstone.    .    .  . 

130-0 

17-2 

Gold  

1013-0 

2-21 

Oak,  live  .... 

70-0 

32-0 

651-0 

4-07 

THE   KNaiNEEIi's  HANDY-BOOK. 


621 


TABLE 


SHOWING  THE  WEIGHT  OF  DIFFERENT  METALS  PER  CUBIC  FOOT, 


Brass 
Copper  . 
Gold  . 
Iron,  cast 
Iron,  wrought 


Lbs. 

525 

Lead,  cast 

550 

Silver 

1,210 

Steel 

450 

Tin,  cast  . 

485 

Zinc 

LbH. 

710 

655 
490 
456 
450 


TABLE 

SHOWING  THE  ACTUAL  EXTENSION  OF  WROUGHT-IRON  AT  VARIOUS 
TEMPERATURES. 

Deg. 

of  Fah.  Length. 

32^........1- 

212   1-0011356 

392   1*0025757 'J  Surface  becomes   straw-colored,  deep- 

672   1*0043253  r    yellow,  crimson,  violet,  purple,  deep- 

752   1-0063894  )     blue,  bright-purple. 

932   1-0087730  I  Surface  becomes  dull,  and  then  bright- 

1,112   1-0114811  i  red. 

1,652   1-0216024^^  .  ,      ,  ...     ,    ^    ,  . 

2192   1-0348242  C yellow,  welding  heat,  white 

2J32    1-0512815  3 

2,912   Cohesion  destroyed.    Fusion  perfect. 

Linear  Expansion  of  Wrought-lron. — The  linear  expansion 
which  a  bar  of  wrought-iron  undergoes,  according  to  Daniell's 
pyrometer,  when  heated  from  the  freezing-  to  the  boiling-point,  or 
from  32^  to  212°  Fah.,  is  about  of  its  length  ;  at  higher  tem- 
peratures the  elongation  becomes  more  rapid.  Thus,  it  will  be 
seen  how  sensible  a  change  takes  place  when  iron  undergoes  a 
variation  of  temperature.  A  bar  of  iron  10  feet  long,  subject  to 
an  ordinary  change  of  temperature  of  from  32°  to  180°  Fah.,  will 
elongate  more  than  ^  of  an  inch,  or  sufficient  to  cause  fracture  in 
stone-work,  strip  the  thread  of  a  screw,  or  endanger  a  bridge, 


622 


THE   engineer's  HANDY-BOOK. 


floor,  roof,  or  truss,  or  even  push  out  a  wall  if  brought  in  contact 
with  it. 

The  expansion  of  volume  and  surface  of  wrought-iron  is  cal- 
culated by  taking  the  linear  expansion  as  unity ;  then,  following 
the  geometrical  law,  the  superficial  expansion  is  twice  the  linear^ 
and  the  cubical  expansion  is  three  times  the  linear. 

Wrought-iron  will  bear  on  a  square  inch,  without  permanent 
alteration,  17,800  pounds,  and  an  extension  in  length  of  yiVtt* 
Cohesive  force  is  diminished  ^q\q  by  an  increase  of  one  degree 
of  heat. 

Compared  with  cast-iron,  its  strength  is  1*12  times,  its  extensi- 
bility 0*86  times,  and  its  stiffness  1*3  times. 

Cast-iron  expands  jq-^^j^-^  of  its  length  for  one  degree  of  heat; 
the  greatest  change  in  the  shade,  in  this  climate,  is  yyVo  '^^^ 
length  ;  exposed  to  the  sun*s  rays,  joV^-  ! 

Cast-iron  shrinks,  in  cooling,  from  -^K  to  ^\  of  its  length. 

Cast-iron  is  crushed  by  a  force  of  93,000  pounds  upon  a  square' 
inch,  and  will  bear,  without  permanent  alteration,  15,300  pounds] 
upon  a  square  inch.  j 

To  find  the  surface  dilatation  of  any  particular  article,  double: 
its  linear  dilatation  ;  and  to  find  the  dilatation  in  volume,  triple! 
it.  To  find  the  elongation  in  linear  inches,  per  linear  foot,  of  anyj 
particular  article,  multiply  its  respective  linear  dilatation,  as  given: 
in  the  table,  by  12. 

TABLE 

SHOWING  THE  LINEAR  DILATATION  OF  SOLIDS  BY  HEAT. 
Length  which  a  Bar  Heated  at  212^  has  greater  than  when  at  the  Temperature  of  Z2P. 


Brass,  cast   0018671 

Copper   0017674 

Gold  ,   0014880 

Iron,  cast   0011111 

Iron,  wrought   0012575 

Silver    0020205 

Steel   0011898 


THE   ENGIJSTEEK^S  HANDY-BOOK. 


623 


TABLE 

DEDUCED  FROM  EXPERIMENTS  ON  IRON  PLATES  FOR  STEAM-BOILERS, 
BY  THE  FRANKLIN  INSTITUTE,  PIIILADA. 

Iron  boiler-plate  was  found  to  increase  in  tenacity,  as  its  tem- 
perature was  raised,  until  it  reached  a  temperature  of  550°  above 
the  freezing-point,  at  which  point  its  tenacity  began  to  diminish. 
At  32°  to  80°  tenacity  is  56,000  lbs.,  or  |  below  its  maximum. 

"    570°  "       "  66,000  "    the  maximum. 

"    720°  "       "  55,000  "    the  same  nearly  as  at  30°. 

"  1050°  "       "  32,000  "    nearly  i  the  maximum. 

u  j240°  "       "  22,000  "    nearly  I  the  maximum. 

"  1317°  "       "   9,000  "    nearly  I  the  maximum. 

It  will  be  seen  by  the  above  table  that  if  a  boiler  should  become 
overheated  by  the  accumulation  of  scale  on  some  of  its  parts,  or 
an  insufficiency  of  water,  the  iron  would  soon  become  reduced  to 
less  than  one-half  its  strength. 

TABLE 

SHOWING  THE  STRENGTH  OF  COPPER  BOILER  PLATES  AT  DIFFERENT 
TEMPERATURES,  DEDUCED  FROM  EXPERIMENTS  BY  THE  FRANKLIN  IN- 
STITUTE OF  PHILA.  THE  STANDARD  STRENGTH  AT  32°  BEING  32,800 
LBS.  PER  SQUARE  INCH. 


Temperature 
above  32°. 

Diminution  of 
Strength. 

Temperature 
above  32°. 

Diminution  of 
Strengtli. 

1 

90° 

0-0175 

9 

660° 

0-3425 

2 

180 

0-0540 

10 

769  . 

0-4398 

3 

270 

0-0926 

11 

812 

0-4944 

4 

360 

0-1513 

12 

880 

0-5581 

5 

456 

0-2046 

13 

989 

0-6691 

6 

460 

0-2133 

14 

1000 

0-6741 

7 

513 

0-2446 

15 

1200 

0-8861 

8 

532 

0-2558 

16 

1300 

1-000 

It  will  be  seen  from  the  above  table,  that,  in  being  heated  from 
the  freezing-point  to  the  boiling-point  of  water,  copper  loses  5 
per  cent,  of  its  strength ;  at  550°  it  loses  about  one-quarter  of  it« 
strength ;  and  at  1332°  loses  all  it«  tenacity. 


624 


THE  ENGINEEE's  HANDY-BOOK 


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THE   ENGINEER'S   HANDY-BOOK.  627 

TABLE 


SHOWING  THE  WEIGHT  OP  CAST-IRON  PIPES,  1  FOOT  IN  LENGTH,  FROM  } 
INCH  TO  li  INCHES  THICK  AND  FROM  3  INCHES  TO  24  INCHES  DIAMETER 


Thickness  in 

Inches. 

ic 

i 



1 

i 

f 

i 

1 

If 

n 

S  * 

Lbs. 

Lbs. 

T  h« 

T,h<a 

T  ha 

Lbs. 

Lbs. 

3 

8} 

12i 

m 

22} 

27i 





3J 

9} 

14i 

19i 

25} 

31} 



4 

10 

161 

22 

28  i 

35 



4i 

llf 

18 

24J 

3U 

38f 





5 

13 

191 

27 

34i 

42} 

50J 

f9 

5^ 

15 

2U 

29i 

37i 

46 

54} 

631 

6 

23  J 

32 

401 

49} 

59 

681 

isi 

*88i 

65 

25i 

34J 

431 

53i 

6Si 

7Si 

84} 

95 

7 

27i 

361 

461 

561 

67} 

781 

89i 

lOU 

7J 

29 

39 

50 

601 

72 

83  J 

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107i 

8 

301 

411 

53 

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88  J 

lOOJ 

1131 

8i 

33 

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56i 

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93  J 

106i 

120 

9 

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98  i 

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125i 

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103 

1171 

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115} 

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156i 

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198 

16 

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143 

166 

187* 

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152i 

178.i 

198} 

2231 

18 

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185i 

209 

235} 

19 

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1951 

222} 

247 

20 

178 

205  i 

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259 

21 

214 

243  i 

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22 

223  J 

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23 

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265  i 

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3101 

628 


TttE  engineer's  handy-book. 


TABLE 

SHOWING  THE  STANDARD  WEIGHTS  OF  CAST-IKON  WATER-PIPE. 


3  inch,  15  lbs.  per  foot 

4  inch,  22  " 
6  inch,  33  " 
8  inch,  42  " 

10  inch,  60  " 
12  inch,  75  " 


=  180  lbs.  per  length  of  12  feet. 
=  264 
400 

=  500 
-=  720 
900 


TABLE 

SHOWING  THE  STANDARD  WEIGHTS  OF  CAST-IRON  GAS-PIPE. 


3  inch,  12J  lbs 

4  inch,  17 
6  inch,  30 
8  inch,  40 

10  inch,  50 
12  inch,  70 


per  foot  =  150  lbs.  per  length  of  12  feet. 
=  204 
=  360 

480 

600 
=  840 


TABLE 

8Hc  ^ING  THE  TENSILE  STRENGTH  OF  VARIOUS  QUALITIES  OF  AMERICAN 


CAST-IRON. 

Breakiug  weight  of 
a  square  inch  bar. 

Common  pig-iron,   15,000 

Good  common  castings,  -   20,000 

Cast-iron            "        .......  20,834 

  19,200 

.......  27,700 

Gun-heads,  specimen  from,   24,000 

"                       "   39,500 

Greenwood  cast-iron,   21,300 

"             "        (after  third  melting,)     .       .       .  45,970 

Mean  of  American  cast-iron,   31,829 

Gun-metal,  mean,  .       ,       ,   37,232 


THE   engineer's   HANDY-BOOK.  629 

English  Cad-Iron.  ^^^^^.^^  ^^i^^, 

a  square  inch  bar. 

Low  Moor,   14,076 

Clyde,  No.  1,   16,125 

Clyde,  No.  3,   23,468 

Calder,  No.  1,   13,735 

Stirling,  mean,   25,764 

Mean  of  English,   19,484 

Stirling,  toughened  iron,   28,000 

Carron  No.  2,  cold-blast,   16,683 

"   2,  hot-blast,   13,505 

"    3,  cold-blast,        .       .       .       .       .       .  13,200 

"   3,  hot-blast,   17,755 

Davon,  No.  3,  hot-blast,   21,907 

Buffery,  No.  1,  cold-blast,   17,466 

"   1,  hot-blast,   13,437 

Cold-Talon  (North  Wales),  No.  2,  cold-blast, .       .       .  18,855 

"    2,  hot-blast,  .       .       .  16,676 


TABLE 

SHOWING  THE  TENSILE  STRENGTH  OF  VARIOUS  QUALITIES  OF  AMERICAN 
WROUGHT-IRON. 


Breaking  weight  of 
a  square  inch  bar. 

From  Salisbury,  Conn.,   66,000 

"    Pittsfield,  Mass.,   67,000 

"    Bellefonte,  Pa.,     .       .       .  .       .       .  58,000 

"    Maramec,  Mo.,  43,000 

"    53,000 

"    Centre  County,  Pa.,   58,400 

Lancaster  County,  Pa., ......  58,061 

"    Carp  River,  Lake  Superior,   89,582 

"    Mountain,  Mo.,  Charcoal  bloom,  ....  90,000 

American  hammered,   53,900 

Chain-iron,   43,000 

Rivets,   53,300 

53* 


630 


THE  engineer's 


HANDY-BOO 


K. 


Breaking  weight  of 
a  square  inch  bar. 


Bolts,  

Boiler-plates,  .... 
Average  boiler-plates, 

"      joints,  double-riveted, 
"  single 
Chrome  steel,  highest  strength, 
"  lowest 
"        "    average  " 
Homogeneous  metal. 


Bessemer  steel. 


2d  quality. 


52,250 
50,000 
55,000 
35,000 
28.600 
198,910 
163,760 
180,000 
105,732 
81,663 
148,324 
154,825 
157,881 


TABLE 

SHOWING  THE  RESULTS  OF  EXPERIMENTS  MADE  ON  DIFFERENT  BRANDS 
OF  BOILER-IRON  AT  THE  STEVENS  INSTITUTE  OF  TECHNOLOGY,  HO- 
BOKEN,  N.  J. 

Thipty-three  experiments  were  made  upon  the  iron  taken  from 
the  exploded  steam-boiler  of  the  ferry-boat  "Westfield."  The 
following  were  the  results : 

Lbs.  per  sq.  in. 

Average  breaking  weight,  41,653 

16  experiments  made  upon  high  grades  of  American 
boiler-plate. 

Average  breaking  weight,    .       .       .       .       .  54,123 
15  experiments  made  upon  high  grades  of  American 
flange-iron. 

Average  breaking  weight,  42,144 

6  experiments  made  upon  English  Bessjemer  steel. 

Average  breaking  weight,   82,621 

5  experiments  made  upon  English  Low  Moor  boiler-plate. 

Average  breaking  weight,   58,984 


THE  ENGINEEK's  IIANDY-BOOK. 


631 


Lb3.  per  sq.  Id 

6  experiments  made  upon  samples  of  tank-iron  taken 
from  different  manufacturers. 

Average  breaking  weight  No.  1,  .       .       .       .  43,831 

No.  2,  .       .       .       .  42,011 

"      No.  3,  .       .       .       .  41,249 
2  experiments  made  on  iron  taken  from  the  exploded 
steam-boiler  of  the  "  Red  Jacket." 

Average  breaking  weight,    .....  49,000 

It  will  be  noticed  that  the  above  experiments  reveal  a  great 
variation  in  the  strength  of  boiler-plate  of  different  grades. 

TABLE 


GIVING  THE  PROPORTIONS  OF  THE  UNITED  STATES  OR  SELLERS'  STANDARD 
THREADS  FOR  SCREWS,  NUTS,  AND  BOLTS. 


eter  of 
cbes. 

h  reads 

Screw 
of  the 
Deci- 
nch. 

C  «  OS 

o  , 

o  <v 

reads 

utside  Diam 
Screw  in  In^ 

umber  of  Tl 
per  Inch 

iameter  -of 
at  the  Root 
Thread  in 
mals  of  an  1 

idth  of  To 
Bottom  of  1 
in  Decimals 
Inch. 

utside  Diam 
Screw  in  In< 

umber  of  Tl 
per  Inch 

iameter  of 
at  the  Root 
Thread  in 
mals  of  an  ] 

idth  of  To 
Bottom  of  '1 
in  Decimals 
Inch. 

O 

O 

Q 

1 

4 

20 

•185 

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2 

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1-712 

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A 

18 

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3 

R 

16 

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4" 

2-176 

•0312 

14 

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•0089 

1' 

4 

2-426 

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1 

13 

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2-629 

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9 

12 

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H 

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8 

11 

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3 

3-317 

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7 
8 

9 

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5 

1-616 

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2i 

5-423 

•0555 

632 


THE   engineer's  HANDY-BOOK. 


The  pitch  "  of  a  thread  is  the  distance  which  it  travels  length- 
ways for  one  revolution  of  the  screw. 

The- thickness  op  depth  of  a  nut,  to  give  equal  strength,  must  be 
equal  to  the  outside  diameter  of  the  screw  or  bolt. 


Speed,  Power,  Capacity,  and  Dress  of  Millstones. 


Diameter  of 
Millstone. 

Re  vol  u  tion  s 
per  Minute. 

Horse-Power. 

Average*  Ca- 
pacity per 
Hour  of 
Orindin^  in 
Bushels. 

Usual  Dress. 

Draught 
froiH  Fore 
Edge  of  Fur- 
row. 

Ft. 

In. 

Inches. 

2 

6 

200 

2^ 

2^ 

7*3 

2 

10 

180 

2f 

2f 

8*2 

3 

0 

170 

3 

3 

9-3 

^ 

3 

2 

160 

H 

3i 

9-3 

2| 

3 

4 

150 

H 

H 

10-3 

3 

3 

6 

140 

3f 

3f 

10-3 

3 

3 

8 

130 

3| 

3? 

10-3 

3 

3 

10 

125 

3| 

Nearly  4 

11-3 

3 

4 

0 

.  120 

4 

4 

10-4 

3 

4 

2 

115 

4| 

4i 

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3 

4 

4 

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4 

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5 

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100 

43 

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H 

4 

10 

95 

5 

6i 

12-4 

4 

5 

0 

90 

6 

7 

12-4 

^ 

Speed  of  Circular-Saws. 

About  nine  thousand  feet  per  minute  for  the  rim  of  a  circular- 
saw  to  travel  may  be  laid  down  as  good  speed :  a  saw  twelve 
inches  in  diameter,  3  feet  around  the  rim,  3,000  revolutions ;  24 
inches  in  diameter,  or  6  feet  around  the  rim,  1,500  revolutions ; 

3  feet  in  diameter,  or  9  feet  around  the  rim,  1,000  revolutions; 

4  feet  in  diameter,  or  12  feet  around  the  rim,  750  revolutions ;  5 
feet  in  diameter,  or  15  feet  around  the  rim,  600  revolutions. 

Rule  for  finding  the  proper  number  of  revolutions  per  minute  of 
any  sized  saw. —  Divide  36,000  by  the  diameter  of  the  saw  in 
inches;  the  quotient  will  be  the  right  number  of  revolutions. 

Example.— 36,000  divided  by  60  equals  600,  the  number  of 
revolutions  a  60-inch  saw  should  make. 


THE    engineer's    11  A  N  D  Y  -  J{  O  C)  K  . 


633 


TABLK 


Sliding 
Surface. 

Surface  at 
Rest. 

Cast-iron. 

Wrought- 
iron. 

Cast-iron. 

Cast-iron. 

Wrought- 
iron. 

Bronze. 

Bronze. 

Wrought- 
iron. 

Cast-iron. 

Bronze. 

Bronze. 

Cast-iron. 

Bronze. 

Bronze. 

Brass. 

Cast-iron. 

Steel. 

it 

Steel. 
Steel. 

Wrought- 

iron. 
Bronze. 

OF  COKFFICIENTS  OF  FRICTIONS  BETWEEN  PLANE  SURFACES. 


State  of  the  Surfaces. 


f  Fibres  of 
I  both  sur- 
faces par- 
allel to 
[  motion. 


Fibres  par- 
allel to 
motion. 


plbg. 


i  lubricated  f  1 
I     with  W 

f  without  lubri 


plbg 


Fibres  of 
iron  pa- 
rallel to 
motion. 


surfaces  unctuous  . 
without  lubricant  . 
surfaces  unctuous  . 

f  tallow 
lubricated  J  lard  . 
with      j  olive-oil 

I  lard  and 
without  lubricant  . 
surfaces  unctuous  . 

lubricated  | 

1  olive-oil 
without  lubricant  . 
surfaces  unctuous  . 

tallow 
lard  and 
olive-oil 
without  lubricant  . 
surfaces  unctuous  . 

lubricated  f  {!*J.|j  ^ 

without  lubricant  . 
surfaces  unctuous  . 
lubricated  I  tallow 

with      \  olive-oil 
without  lubricant  . 
surfaces  unctuous  . 
lubricated  with  olive- 
without  lubricant  . 
surfaces  unctuous  . 

lubricated  f  ['"^^jP^^ 

with  ••. 

(  olive-oil 

without  lubricant  . 

,l"''ru;ated||j7 

with  ]  -1 
I  { olive-oil 

lubricated  f  tallow 

with       (  lard  . 

without  lubricant  . 

I  lubricated  (^^'j!'^^^ 
1      ^^.^j^      -  olive-oil 

[  ^       (  lard  and  plbg. 


oil 


Coeffi-  \ 
cieiit  of 
Friction. 


634 


THE   engineer's  HANDY-BOOK. 


Non-Conducting  CoYering  for  Steam-Boilers  and  Pipes. 

Make  a  thin  paste  by  boih"ng  floup  and  water,  then  stir  in  as 
much  sawdust  as  it  can  hold  together.  After  drying,  it  will  adhere 
to  iron  when  slightly  warm,  after  which  several  coats  may  be 
applied  in  succession.  It  may  be  made  water-proof  by  painting 
with  coal-tar. 

Or,  mix  thoroughly  equal  parts  of  fuller's-earth  and  finely-sifted 
coal-ashes  ;  add  to  tlie  pasty  mass  a  small  quantity  of  calves-hair. 
Before  laying  it  on  a  pipe,  add  i  its  quantity  of  calcined  gypsum, 
and  lay  on  in  thin  layers.  The  pipe  or  cylinder  should  be  warm 
when  the  mass  is  applied. 

The  annexed  out  represents  what  is  known  to  mechanics  as  an 
expansion-joint,  such  as  is  used  on  short,  straight  steam-pipes  in 
^  „    .  contracted  places,  for  the 


purpose  of  preventing 
them  from  breaking  or 
throwing  the  machinery 
out  of  line  by  the  force 
of  expansion.  A  shows 
the  socket,  or  stufiing- 
box;  By  the  tube  or  pipe; 
C,  the  guide  employed 
for  the  purpose  of  keep- 
ing the  pipe  straight;  F  F,  the  studs  by  which  the  gland  is  ad- 
justed, and  the  guide,  (7,  retained  in  position ;  a  a  is  the  cavity 
which  contains  the  fibrous  packing  for  the  purpose  of  preventing 
leakage ;  e  e,  the  recess  into  which  the  head,  2),  is  drawn  Avhen  the 
pipe  contracts;  and  G  the  female  tube  into  which  it  is  forced 
by  expansion. 

Cement  for  steam -joints  and  patching  steam-boilers,  —  Take 
any  desired  quantity  of  pure  red  lead,  put  it  in  an  iron  mortar,  on 
a  block  or  thick  plate  of  iron.  Put  in  a  quantity  of  white  lead 
ground  in  oil;  knead  them  until  you  make  a  thick  putty;  then 
pound  it ;  the  more  it  is  pounded  the  softer  it  will  become.  Roli 


THE   engineer's   HANDY-BOOK.  635 

in  red  lead,  and  pound  again ;  repeat  this  operation  of  adding  red 
lead  and  pounding,  until  the  mass  becomes  a  stiff  putty.  In  ap- 
plying it  to  the  flange  or  joint,  it  is  well  to  put  a  thin  grummet 
around  the  orifice  of  the  pipe,  to  prevent  the  cement  being  forced 
inward  to  the  pipe  when  the  bolts  are  screwed  up.  When  the 
flanges  are  not  faced,  make  the  above  mass  rather  soft,  and  add 
cast-iron  borings  run  through  a  fine  sieve,  when  it  will  be  found 
to  resist  either  fire  or  water. 

Op,  powdered  litharge,  2  parts ;  very  fine  sand,  2  parts ;  slaked 
quicklime,  1  part.  Mix  all  together.  So  use.  Mix  the  proper 
quantity  with  boiled  linseed-oil,  and  apply  quickly.  It  gets  baud 
very  soon. 

Or,  white  lead  ground  in  oil,  10  parts;  black  oxide  of  manga- 
nese, 3  parts ;  litharge,  1  part.  Reduce  to  the  proper  consistency 
with  boiled  linseed-oil,  and  apply. 

Or,  red  lead  ground  in  oil,  6  parts ;  white  lead,  3  parts ;  oxide 
of  manganese,  2  parts ;  silicate  of  soda,  1  part ;  litharge,  J  part ; 
all  mixed  and  used  as  putty. 

Or,  take  10  pounds  of  ground  litharge  ;  4  lbs.  of  ground  Paris 
white ;  J  pound  of  yellow  ochre  and  J  oz.  of  hemp ;  cut  into 
lengths  of  I  inch ;  mix  all  together  with  boiled  linseed-oil  to  the 
consistency  of  a  stiff  putty.  This  cement  resists  fire  and  will  set 
in  water. 

Cement  for  rust-joints. — Cast-iron  borings  or  turnings,  19 
lbs. ;  pulverized  sal-ammoniac,  1  pound  ;  flour  of  sulphur,  i  pound. 
It  should  be  thoroughly  mixed,  and  passed  through  a  tolerably 
fine  sieve.  SuflScient  water  should  be  added  to  wet  the  mixture 
through.  It  should  be  prepared  some  hours  before  use.  A  small 
quantity  of  sludge  from  the  trough  of  a  grindstone  will  improve 
its  quality. 

All  movable  joints  of  the  best  description  of  land-  and  marine- 
engines  are  now  faced  on  a  lathe  or  planer,  and  then  rendered 
perfectly  steam-,  air-,  and  water-tight  by  filing  and  scraping,  so 
that  all  that  is  necessary,  when  put  together,  is  to  oil  their  sur- 
faces. 


636 


THE   engineer's  HANDY-BOOK. 


Fop  smooth  surfaces  that  can  be  conveniently  calked,  sheet- 
copper,  annealed  by  heating  to  a  cherry  red  and  then  plunging  it 
into  cold  water,  makes  a  permanent  joint. 

Lead -wire  makes  a  very  cheap,  clean,  and  permanent  joint. 
Copper- wire  also  makes  a  good  joint ;  but,  when  convenient,  it  is 
always  best  to  plane  or  turn  a  groove  in.  one  of  the'surfaces  to  be 
brought  into  contact. 

For  uniform  surfaces,  gauze  wire-cloth  coated  on  either  side 
with  white  or  red  lead  paint  makes  a  very  durable  joint,  particu- 
larly where  it  is  exposed  to  high  temperatures. 

♦  For  pumps  or  stand-pipes  in  the  holds  of  vessels,  canvas  well 
saturated  on  both  sides  with  white  or  red  lead  makes  a  very  dur- 
able joint.  Pasteboard  painted  on  both  sides  with  white  or  red 
lead  paint  is  frequently  used  with  good  results. 

How  to  make  a  good  adhesive  cement.  —  Mix  pulverized 
gum- Arabic  with  its  weight  of  finely-powdered  calcined  alum. 
When  mixed  with  a  small  quantity  of  water,  it  forms  a  cement 
which  unites  wood,  paper,  porcelain,  glass,  and  crockery  very  firmly. 
It  must  be  kept  dry  in  powder  and  moistened  only  as  needed. 

A  cement  for  leather  may  be  made  by  dissolving  in  a  mixture 
of  ten  parts  of  bi-sulphide  of  carbon  and  one  part  of  oil  of  turpen- 
tine enough  gutta-percha  to  thicken  the  composition.  The  leather 
must  be  freed  from  grease,  which  may  be  done  by  placing  a  cloth 
between  the  leather  and  a  hot  iron.  The  pieces  cemented  must  be 
pressed  together  until  the  cement  is  dry. 

A  cement  for  fastening  leather  to  iron,  china,  or  glass.  —  To 
one  quart  of  glue  dissolved  in  good  cider  vinegar  add  one  ounce 
of  good  Venice  turpentine.  It  should  be  allowed  to  simmer  about 
half  a  day. 

Cement  for  leather  belting.  — Of  common  glue  and  American 
isinglass,  take  equal  parts ;  place  in  a  kettle,  and  add  suflacient 
water  to  cover  the  whole.  Let  them  soak  ten  hours ;  then  bring 
the  mixture  to  the  boiling  point,  and  add  pure  tannin,  until  the 
whole  becomes  ropy,  or  appears  like  the  white  of  eggs.  Apply  it 
warm.  Buff  the  grain  off  the  leather  where  it  is  to  be  cemented ; 


THE   engineer's  HANDY-HOOK. 


637 


rub  the  joint  surfaces  solidly  together,  and  let  it  dry  for  a  few 
hours. 

Cement  for  rubber  belting.  —  Take  16  parts  of  gutta-percha 
or  India-rubber;  2  parts  common  pitch;  and  1  part  linseed- 
oil.  Melt  together,  and  use  hot.  This  cement  will  unite  leather 
or  rubber  that  has  not  been  vulcanized. 

Cement  for  brass  and  glass.  —  Boil  3  parts  of  resin  with  1 
part  of  caustic  soda  and  5  of  water.  Add  five  times  its  weight 
of  plaster  of  Paris.  It  sets  firmly  in  from  half-  to  three-quarters 
of  an  hour.  Zinc,  white  lead,  or  precipitated  chalk  may  be  sub- 
stituted for  plaster,  but  hardens  more  slowly. 

Cement  for  stone  or  marble.  —  The  best  cement  for  mending 
marble,  or  any  kind  of  stone,  is  made  by  mixing  20  parts  of  lith- 
arge and  1  part  of  freshly-burned  lime  in  fine,  dry  powder.  This 
is  made  into  a  putty  by  the  addition  of  linseed-oil.  It  sets  in  a 
few  hours,  having  the  appearance  of  light  stone. 

Belting. 

While  the  use  of  belts  for  the  transmission  of  power  is  not  an 
American  invention,  the  numerous  improvements  made  in  this 
country  have  caused  it  to  be  known  in  Europe  as  the  American 
system.  In  Europe  the  greater  part  of  the  power  is  transmitted 
by  cog-w^heels,  but  in  this  country  99  per  cent,  is  transmitted  by 
belting.  The  latter  is  used  everywhere,  from  the  sewing-machine 
to  the  500  horse-power  engine  of  the  largest  factory. 

Belts  can  be  run  in  any  way,  at  any  angle,  of  any  length,  and 
at  any  speed,  and  can  be  put  up  by  any  one  of  ordinary  skill. 
They  can  be  made  of  any  flexible  material  —  leather,  rubber, 
gutta-percha,  or  cloth ;  yet,  while  so  hardy  and  so  popular,  they 
have  one  fault  —  they  are  not  positive.  If  the  motion  makes  a 
certain  number  of  revolutions,  a  portion  of  them  is  lost  with 
every  belt  used.  This  is  the  only  fault  of  the  system.  It  is  noise- 
less, yielding,  and  regular ;  but,  unlike  cog-wheels,  it  is  not  posi- 
64 


•638 


THE   ENGINEER'S  HANDY-BOOK. 


tive.  The  number  of  revolutions  that  are  lost  may,  and  do,  vary 
continually  by  changes  of  the  load  or  of  the  atmosphere. 

Belts  derive  their  power  to  transmit  motion  from  the  friction 
between  the  surface  of  the  belt  and  the  pulley,  and  from  nothing 
else,  and  are  governed  by  the  same  laws  as  in  friction  between  flat 
surfaces.  The  friction  increases  regularly  with  the  pressure.  The 
great  difference  often  observed  in  the  friction  of  belts  is  due  simply 
to  their  elasticity  of  surface ;  that  is,  the  more  elastic  the  surface 
the  greater  the  friction. 

In  taking  power  from  any  source  of  motion,  there  are  two  points 
which  control  us ;  all  the  others  we  can  control  and  modify  to  a 
certain  extent.  Ordinary  belts  will  sustain  safely  a  working  ten- 
sion of  45  lbs.  per  inch  in  width ;  the  rule  to  determine  the  width 
of  belt  and  size  of  pulley  required  to  transmit  a  given  horse-power 
is  easily  found.  Since  a  horse-power  is  33,000  pounds  raised  one 
foot  high  per  minute,  we  must  adjust  the  width  and  velocity  of 
belts  so  as  to  effect  the  required  result.  Thus,  if  the  belt  moves 
with  a  velocity  of  733  feet  per  minute,  a  belt  five  inches  wide 
will  transmit  five  horse-power,  provided  the  effective  tension  is  45 
lb&.  per  inch.  If  the  velocity  be  increased  to  1466  feet  per  min- 
ute, the  same  belt  with  the  same  tension  will  transmit  ten  horse- 
power.  So  that  a  five-inch  belt,  applied  to  a  five-foot  pulley  mak- 
ing 120  revolutions  per  minute,  would  transmit  ten  horse-power 
when  the  effective  tension  is  225  pounds. 

By  taking  the  actual  effective  tension  of  the  belt,  and  multiply- 
ing it  by  the  actual  velocity,  we  get  what  may  be  called  the  in- 
dicated horse-power  of  the  belt,  which  corresponds  to  the  indicated 
horse-power  of  the  engine.  And,  finally,  by  measuring  the  act- 
ual power  transmitted  —  which  may  be  done  by  means  of  a  dyn- 
amometer—  we  can  get  the  actual  power  transmitted.  Eules 
based  upon  the  amount  of  belt  surface  in  contact  with  the  pulley, 
and  on  similar  data,  cannot  be  made  to  give  reliable  results.  For 
practical  purposes,  velocity  and  power  to  resist  tension  are  the 
only  available  elements  of  the  calculation.  Actual  tension,  adhe- 
sion, friction,  etc.,  can  all  be  varied  at  will,  and  consequently  form 


THE   engineer's   HANDY-BOOK.  639 

no  certain  dependence  for  the  calculations  of  the  machinist  and 
engineer. 

On  the  scientific  principle  that  the  adhesion,  and  consequently 
the  capability  of  leather  belts  to  transmit  power  from  motors  to 
machines,  is  in  proportion  to  the  pressure  of  the  actual  weight  of 
the  leather  on  the  surface  of  the  pulley,  it  is  manifest  that,  as 
longer  belts  have  more  weight  than  shorter  ones,  and  that  broader 
belts  of  the  same  length  have  more  weight  than  narrower  ones,  it 
may  be  adopted  as  a  rule  that  the  adhesion  and  capability  of  belts 
to  transmit  power  are  in  the  ratio  of  their  relative  lengths  and 
breadth.  A  belt  of  double  the  length  or  breadth  of  another 
under  the  same  circumstances,  will  transmit  more  than  double  the 
power.  For  this  reason  it  is  desirable  to  use  long  belts.  By 
doubling  the  velocity  of  the  same  belt,  its  effectual  capability  for 
transmitting  power  is  also  doubled. 

Good  stock  is  the  first  requirement  of  a  belt,  which,  if  spongy, 
will  not  meet  that  demand.  It  must  be  firm,  but  pliable;  the 
grain  or  hair  side  should  be  free  from  wrinkles ;  the  stock  should 
show  no  irregularities  in  dressing,  but  be  of  an  even  thickness 
throughout;  the  splices  should  be  mathematically  true,  and  if 
rivets  are  employed,  they  should  be  inserted  on  the  hair  side,  and 
the  burrs  sent  home  before  riveting ;  the  edges  should  be  parallel 
and  perfectly  straight.  In  handling  a  belt,  examine  it  carefully, 
double  it  up,  the  hair  side  out,  and  press  it  together ;  if  it  crack 
under  this  treatment,  it  should  be  rejected,  as  the  rational  use  of  a 
belt  consists  in  utilizing  the  whole  amount  of  power  it  will  trans- 
mit. 

Belts  are  sometimes  used  having  a  transmitting  power  of  double 
the  capacity  necessary  where  they  are  employed,  while  quite  as 
often  they  are  much  too  narrow  for  the  work  required^of  them. 
The  first  instance  shows  a  useless  waste  of  material,  the  latter 
poor  economy ;  as,  in  order  that  it  may  perform  the  work  required, 
it  is  necessary  frequently  to  take  it  up,  as  a  result  of  which  the 
weak  points  succumb  to  the  strain,  and  it  is  torn  asunder ;  or  if 
not,  the  shaft  is  likely  to  be  drawn  out  of  line,  or  the  bearing  ovei* 
heated. 


o40 


THE   ENGINEER'S  HANDY-BOOK. 


In  using  a  new  belt  a  few  days,  if  it  present  a  mottled  appear- 
ance on  the  side  next  to  the  pulkys,  it  may  be  set  down  that  it  is 
not  furnishing  the  full  capacity  of  its  power.  The  spots  referred 
to  indicate  that  certain  portions  of  the  belt  do  not  touch  the 
pulley,  and  that  its  entire  transmitting  power  is  not  utilized.  If 
the  face  of  the  pulley  is  true,  and  the  belt  is  as  nearly  perfect  as 
possible,  the  defect  may  be  remedied  by  the  judicious  application 
of  rendered  tallow  and  fish  oil,  two  parts  of  tallow  to  one  of  oil, 
melted  and  allowed  to  cool.  A  new  belt  should  be  used  a  day  or 
two  before  it  is  oiled,  and  frequent  application  of  small  quantities 
are  better  than  too  liberal  oiling  at  long  intervals. 

If  a  belt,  of  the  proper  size  for  the  work  it  has  to  do,  slip  on  the 
pulley,  it  is  caused  by  the  centrifugal  force,  which  tends  to  throw 
it  outward;  a  corresponding  degree  of  tension  will  check  the 
defect. 

Belts  should  be  put  on  by  a  person  acquainted  with  their  use, 
as  the  wear  of  the  belt  depends  considerably  on  the  manner  in 
which  it  is  put  on ;  therefore,  the  following  suggestions,  if  prac- 
tised, will  be  of  much  service  to  persons  employed  in  this  capac- 
ity. The  ends  to  be  joined  should  be  cut  perfectly  square,  in 
order  that  one  side  may  not  be  drawn  tighter  than  the  other. 
Good  lace-leather,  if  properly  used,  will  give  better  satisfaction 
than  any  patent  fastening. 

Where  belts  run  vertically,  they  should  always  be  drawn  moder- 
ately tight,  or  the  weight  of  the  belt  will  not  allow  it  to  adhere 
closely  to  the  lower  pulley ;  but  in  all  other  cases  they  should  be 
slack.  In  many  instances,  the  tearing  out  of  lace-holes  is  unjustly 
attributed  to  poor  belting;  when,  in  reality,  the  fault  lies  in  having 
a  belt  too  short,  and  trying  to  force  it  together  by  lacing,  and  the 
more  the  leather  has  stretched  while  being  manufactured,  the  more 
liable  it  is  to  be  complained  of. 

To  obtain  the  greatest  amount  of  power  from  belts,  the  pulleys 
should  be  covered  with  leather.  This  will  allow  the  belts  to  be 
ran  very  slack,  and  give  25  per  cent,  more  wear. 

More  power  can  be  obtained  from  using  the  grain  side  of  a  belt 


THE   engineer's    HANI)  f-BOOK. 


641 


to  the  pulley  than  from  the  flesh  side,  as  the  belt  adheres  more 
closely  to  the  pulley ;  but  it  should  be  remembered  that  the  belt 
will  not  last  quite  so  long,  as  when  the  grain,  which  is  very  thin, 
is  worn  off,  the  substance  of  the  belt  is  gone. 

Double-leather  belts  are  frequently  used ;  but  it  is  clearly  a 
mistake,  as  a  single-leather  one  will  transmit  more  of  the  power 
than  a  double  one.  Double-leather  belts  run  straighter  than  single 
ones,  as  the  flank  side  of  one  part  can  be  put  against  the  back 
of  the  others.  A  double  belt  will  stand  a  greater  tension  than  a 
single  one,  but  a  single  belt  will  stand  all  that  should  be  put  upon 
any  belt. 

In  cases  where  a  belt  is  incapable  of  transmitting  the  required 
amount  of  power,  and  circumstances  preclude  the  possibility  of 
substituting  a  wider  one,  the  difficulty  may  be  overcome  by  using 
two  belts  of  the  same  width,  one  on  the  top  of  the  other.  Two 
belts  run  in  this  way  will  transmit  nearly  as  much  power  as  one 
belt  the  width  of  the  two. 

How  to  test  the  quality  of  leather  for  belting. —  Cut  a  small 
strip  of  the  leather  about  j'g  of  an  inch  in  thickness,  and  place  it 
[  in  strong  vinegar.  If  the  leather  has  been  thoroughly  tanned, 
and  is  of  good  quality,  it  will  remain  for  months  even  immersed, 
without  alteration,  simply  becoming  a  little  darker  in  color.  But, 
on  the  contrary,  if  not  thoroughly  tanned,  the  fibres  will  quickly 
swell,  and,  after  a  short  period,  become  transformed  into  a  gela- 
tinous mass. 

How  to  make  belts  run  on  the  centre  of  pulleys. — It  is  a  com- 
mon occurrence  for  belts  to  run  on  one  side  of  the  pulleys.  This 
arises  from  one  or  two  causes :  1st,  One  or  both  of  the  pulleys 
may  be  conical,  and,  of  course,  the  belt  will  run  on  the  higher 
side.  The  most  effectual  remedy  for  this  will  be  to  straighten 
the  face  of  the  pulleys.  2d,  The  shafts  may  not  be  parallel  or 
exactly  in  line.  In  this  case  the  belt  will  incline  off  to  the  side 
where  the  ends  of  the  shafts  come  the  nearest  together.  The  rem- 
edy in  this  case  would  be  to  slack  up  on  the  hanger-bolts,  and 
drive  the  hangers  out  or  in,  as  the  case  may  be,  until  both  ends  of 
64*  2Q 


642         THE  engineer's  handy-book. 


the  shafts  become  exactly  parallel.  This  can  be  determined  bj 
getting  the  centres  of  the  shafts  at  both  ends  by  means  of  a  long 
lath  or  light  strip  of  board. 

Tighteners.— The  tightener  should  be  placed  as  close  to  the 
large  or  driving-pulley  as  circumstances  will  permit,  as  the  loss 
of  power  incurred  by  the  use  of  the  tightener  is  equal  to  that  re- 
quired to  bend  the  belt  and  carry  the  tightening-pulley.  Conse- 
quently, there  is  a  greater  loss  of  power  by  placing  it  near  the 
small  pulley,  as  the  belt  is  required  to  be  bent  more  than  when  it 
is  placed  near  the  large  one. 

The  reason  why  belts  run  to  the  highest  side  of  a  pulley  is  due, 
in  part,  to  centrifugal  force,  and  also  to  the  fact  that  the  part  of 
a  belt  nearest  the  highest  part  of  a  rounded  pulley  is  more  rap- 
idly drawn,  because  the  circumference  of  the  pulley  is  greater  at 
that  point. 

Rubber  and  leather  belts.— Rubber  belts  will  transmit  nearly 
as  much  power  as  leather  belts  with  the  same  tension ;  and  they 
have  this  Sidvantage,  that  they  may  be  made  of  any  length,  width, 
or  thickness,  and  yet  always  run  straight,  providing  the  pulleys 
are  in  line.  Besides,  their  first  cost  is  much  less  than  those  of 
leather ;  but  they  will  not  last  over  half  as  long.  They  cannot 
be  run  in  situations  where  the  belt  rubs,  nor  as  cross-belts,  or 
through  forks,  as  shifting-belts;  and  when  they  give  out,  it  is 
almost  impossible  to  repair  them. 

If  a  rubber  belt  runs  off,  and  becomes  entangled  in  the  machin- 
ery, ten  chances  to  one  it  will  be  completely  ruined ;  whereas,  a 
leather  belt,  under  like  circumstances,  will  sustain  very  little 
injury.  When  saturated  with  oil,  they  soon  rot,  and  when  situa- 
ted in  cold,  damp  places,  they  are  liable  to  freeze,  which  has  a 
tendency  to  separate  the  different  thicknesses  and  ruin  the  belt. 
Besides,  they  often  freeze  to  the  face  of  pulleys  when  standing 
still,  and  when  started  up,  the  gum  facing  is  torn  off,  which  ruins 
the  belt. 

A  leather  belt,  if  made  of  good  stock,  not  overstrained  and 
properly  treated,  will  last  for  twenty  years.    When  partly  worn 


THE   engineer's  HANDY-BOOK. 


643 


out,  it  may  be  cut  up  and  used  over  again  for  a  narrower  or 
shorter  belt ;  and  when  entirely  unfit  for  the  transmission  of  power, 
it  may  be  used  for  different  purposes  around  a  factory ;  but  when 
rubber  belts  are  worn  out,  they  are  of  no  value  whatever. 

To  prevent  accidents  by  shafts  revolving  within  reach  of  opera- 
tives^ garments  in  mills  and  factories, —  Cover  the  shaft  with  a  loose 
sleeve  of  sheet-tin  or  zinc,  and  insert  a  ring  of  thick  gum  or  leather 
at  each  end,  to  prevent  rattling.  Should  it  become  entangled  with 
the  garments  of  any  of  the  operatives,  the  resistance  will  cause 
the  sleeve  to  stand  still  while  the  shaft  is  rotating  within  it,  by 
which  the  person  may  be  extricated  and  accident  averted. 

Rule  for  finding  the  length  of  belt  wanted, — Add  the  diameter  of 
the  two  pulleys  together ;  divide  the  sum  by  2,  and  multiply  the 
quotient  by  3i.  Add  the  product  to  twice  the  distance^  between 
the  centres  of  the  shafts,  and  the  sum  will  be  the  length  required. 

Another  rule  for  finding  the  length  of  a  belt. — Add  the  diam- 
eter of  the  two  pulleys  together,  multiply  by  3i,  divide  the  pro- 
duct by  2,  add  the  quotient  to  twice  the  distance  between  the  cen- 
tres of  the  shafts,  and  you  have  the  length  required. 

Rule /or  finding  the  ividth  of  belt  to  transmit  a  given  horse-power, 
—  Multiply  36,000  by  the  number  of  horse-power;  multiply  the 
speed  of  the  belt  in  feet  per  minute  by  one-half  the  length  in 
inches  of  belt  in  contact  with  smaller  pulley;  divide  the  first 
product  by  the  second ;  the  quotient  will  be  the  required  width 
in  inches. 

Rule  for  calculating  the  number  of  horse-powers  a  belt  will  trans- 
mit^ its  velocity,  and  the  number  of  square  inches  in  contact  with  the 
smaller  pulley  being  given, —  Divide  the  number  of  square  inches 
in  contact  with  the  pulley  by  2  ;  multiply  this  quotient  by  the 
velocity  of  the  belt  in  feet  per  minute,  and  divide  by  36,000. 
The  quotient  is  the  number  of  horse- powers  the  belt  will  transmit. 

Another  rule. —  Divide  the  number  of  square  inches  of  belt  in 
contact  with  the  pulley  by  2 ;  multiply  this  quotient  by  the  ve- 
locity of  the  belt  in  feet  per  minute  ;  divide  this  amount  by  32,000, 
and  the  quotient  will  be  the  number  of  horse-power. 


644 


THE   engineer's  HANDY-BOOK. 


Rule  for  finding  the  change  required  in  the  length  of  a  belt  when 
one  of  the  pulleys  on  ivhich  it  runs  is  changed  for  one  of  a  different 
size. — Take  three  times  the  difference  between  the  diameters  of 
the  pulleys  and  divide  by  2.  The  result  will  be  the  length  of 
belt  to  cut  out  or  put'in. 

How  to  measure  a  coil  of  belting. — Add  the  diameter  of  the 
hole,  in  inches,  to  the  outside  diameter  of  the  roll ;  multiply  by 
the  number  of  coils  in  the  roll ;  then  multiply  this  by  the  decimal 
•1309,  and  the  product  will  be  the  number  of  feet  in  the  roll.  To 
have  the  exact  length,  the  average  diameter  must  be  used  if  the 
roll  is  not  perfectly  round,  and  fractional  parts  of  an  inch  must 
not  be  omitted  in  the  calculation. 

How  to  put  on  a  belt. — Never  place  a  belt  on  the  pulley  in 
motion ;  iilways  place  it  first  on  the  loose  pulley  or  the  pulley  at 
rest ;  then  run  it  on  the  pulley  in  motion.  If  the  belt  is  very 
heavy,  and  the  pulleys  run  at  a  very  high  speed,  it  is  advisable  to 
slack  on  the  speed  of  the  engine ;  but  when  this  is  impracticable 
or  inconvenient,  care  must  be  taken  to  mount  the  belt  on  the  exact 
face.  The  person  engaged  in  so  doing  must  have  a  firm  footing, 
and  prevent  his  clothing  from  getting  in  contact  either  with  the 
belt  or  pulley.  Where  the  belt  is  heavy,  and  the  location  such 
that  it  is  impossible  to  get  a  solid  footing  and  exert  strength  in 
running  on  the  belt,  it  is  best  to  stop  the  engine  and  mount  the 
belt  on  the  pulley  as  far  as  possible.  Then  take  a  small  rope, 
double  it,  slip  one  end  through  the  arms  and  around  the  belt  and 
rim  of  the  pulley,  and  the  other  end  through  the  loop  formed  by 
the  double  of  the  rope ;  then  stand  on  the  floor  on  the  opposite 
side,  and  draw  oh  the  rope,  when  the  belt  will  be  hugged  to  the 
periphery  of  the  pulley.  When  motion  is  communicated,  it  may 
be  slipped  on  without  any  trouble,  while  by  letting  go  the  end  of 
the  rope  when  the  belt  is  on  the  pulley,  the  noose  will  be  undone 
and  the  rope  thrown  off. 

Rule  for  finding  the  required  size  of  a  driving-pulley  for  any  re- 
quired speed. —  Multiply  the  diameter  of  the  driven  pulley  by  the 
number  of  revolutions  it  should  make,  and  divide  the  product 


THE   engineer's  HANDY-BOOK. 


646 


the  revolutions  of  the  driver.  The  quotient  will  be  tlie  required 
size  of  driver. 

Rule  for  finding  the  diameter  of  a  driven  pulley  for  a  given 
number  of  revolutionSy  the  diameter  and  revolutions  of  the  driver 
being  known,- — Multiply  the  diameter  of  the  driver  by  its  num- 
ber of  revolutions,  and  divide  the  product  by  the  number  of 
revolutions  of  the  driven  pulley.  The  quotient  will  give  the 
proper  size  of  the  driven  pulley. 

Gearing. 

1{\x\q  for  finding  the  diameter  of  toothed  wheels. —  Multiply  the 
number  of  teeth  by  the  number  of  thirty-seconds  of  an  inch  con- 
tained in  the  pitch,  the  product  will  be  the  diameter  in  inches  and 
hundredths  of  an  inch  ;  or,  multiply  the  number  of  teeth  by  the 
true  pitch,  and  the  product  by  '3184.  These  results  give  only  the 
diameter  between  the  pitch-line,  on  one  side,  and  the  same  line  on 
the  other  side,  and  not  the  entire  diameter  from  point  to  point  of 
teeth  on  opposite  sides.  It  must  also  be  borne  in  mind  that  these 
results  are  only  approximate  diameters,  since  the  wheel  often  varies 
from  the  computed  diameter  in  consequence  of  shrinkage  and  other 
causes. 

Rule  for  finding  the  required  number  of  teeth  in  a  pinion  to  have 
any  given  velocity. — Multiply  the  velocity  or  number  of  revolutions 
of  the  driver  by  its  number  of  teeth  or  its  diameter,  and  divide 
the  product  by  the  desired  number  of  revolutions  of  the  pinion  or 
driven. 

Rule  for  finding  the  diameter  of  a  pinion,  when  the  diameter  of 
the  driver  and  the  number  of  teeth  in  driver  and  pinion  are  given. — 
Multiply  the  diameter  of  the  driver  by  the  number  of  teeth  in  the 
pinion,  and  divide  the  product  by  the  number  of  teeth  in  the  driver, 
and  the  quotient  will  be  the  diameter  of  pinion. 

Rule  for  finding  the  number  of  revolutions  of  a  pinion  or  driven, 
when  the  number  of  revolutions  of  driver  and  the  diameter  or  the 
number  of  teeth  of  driver  and  driven  are  given. —  Multiply  the 


646 


THE   ENGINEER'S  HANDY-BOOK. 


number  of  revolutions  of  driver  by  its  number  of  teeth  or  its 
diameter,  and  divide  the  product  by  the  number  of  teeth  or  the 
diameter  of  the  driven. 

Rule  for  finding  the  number  of  revolutions  of  a  driver,  when  the 
revolutions  of  driven  and  teeth,  or  diameter  of  driver  and  driven,  are 
given. —  Multiply  the  number  of  teeth  or  the  diameter  of  driven 
by  its  revolution^,  and  divide  the  product  by  the  number  of  teeth 
or  the  diameter  of  driver. 

Rule  for  finding  the  number  of  revolutions  of  the  last  wheel  at  the 
end  of  a  train  of  spur-wheels,  all  of  which  are  in  a  line,  and  mesh 
into  one  another,  when  the  revolutions  of  the  first  wheel,  and  the 
number  of  teeth,  or  the  diameter  of  the  first  and  last  are  given,  — 
Multiply  the  revolutions  of  first  wheel  by  its  number  of  teeth  or 
its  diameter,  and  divide  the  product  by  the  number  of  teeth  or 
the  diameter  of  the  last  wheel ;  the  result  is  its.  number  of  revo- 
lutions. 

Rule  for  finding  the  number  of  revolutions  in  each  wheel  for  a  train 
of  spur-wheels,  each  to  have  a  given  velocity, —  Multiply  the  number 
of  revolutions  of  the  driving-wheel  by  its  number  of  teeth,  and 
divide  the  product  by  the  number  of  revolutions  each  wheel  is  to 
make.  The  result  will  be  the  number  of  teeth  required  for 
each. 

Rule  for  finding  the  number  of  revolutions  of  the  last  wheel  in  a 
train  of  wheels  and  pinions,  spurs  or  bevels,  wheii  the  revolutions  of 
the  first  or  driver,  and  the  diameter,  the  teeth  or  the  circumference  of 
all  the  drivers  and  pinions,  are  given, —  Multiply  the  diameter,  the 
circumference,  or  the  number  of  teeth  of  all  the  driving-wheels 
together,  and  this  continued  product  by  the  number  of  revolutions 
of  the  first  wheel;  and  divide  this  product  by  the  continued  prod- 
uct of  the  diameter,  the  circumference,  or  the  number  of  teeth  of 
all  the  pinions,  and  the  quotient  will  be  the  number  of  revolutions 
of  the  last  wheel. 


647 


648 


THE    engineer's  HANDY-BOOK. 


Fitchburg  Steam-Engine  Company^s  Automatic  Cut-OflP 

Engine. 

The  cut  on  page  647  represents  the  Fitchburg  horizontal,  auto- 
matic, cut-off  engine,  with  positive  valve-gear  and  independent 
steam  and  exhaust  arrangements.  As  will  be  observed,  the  frame 
is  of  the  girder  pattern,  faced  up  at  one  end  to  receive  the  cylin- 
der and  the  other  the  pillow-block.  The  legs,  which  support  the 
cylinder  and  main-bearing,  are  bolted  to  foundation-plates,  which 
prevents  the  possibility  of  any  movement.  The  steam-valves 
receive  their  motion  from  a  movable  eccentric,  with  variable 
throw,  and  admits  or  cuts  off  the  steam  at  any  desired  point  in 
the  stroke,  to  meet  the  requirements  of  load  and  pressure.  The 
exhaust-valves  are  worked  by  a  direct  movement  from  an  eccen- 
tric keyed  on  the  sliaft. 

The  governor,  a  cut  of  which  may  be  seen  on  page  649,  is 
placed  on  the  main  shaft,  is  enclosed  in  a  disc,  and  is  the  same  in 
principle,  though  differing  somewhat  in  mechanism  from  that  used 
on  the  Buckeye  engine.  It  is  claimed  to  be  very  sensitive  and 
powerful,  thus  ensuring  a  steady  motion  under  the  most  varying 
loads  and  steam-pressures,  which  is,  of  itself,  a  desideratum  of 
great  importance,  as  any  increase  in  speed  over  that  at  which  the 
engine  was  intended  to  run,  is  a  waste  of  steam,  and  consequently 
a  waste  of  fuel ;  and  as  any  lagging  of  an  engine  behind  the 
regular  speed  at  times  induces  a  loss  of  production.  Because,  it 
is  well  known  that  to  produce  economical  results,  the  valve-gear 
must  be  so  arranged  as  to  admit  the  necessary  volume  of  steam  to 
the  cylinder  at  the  right  time,  and  no  more. 

S'S  is  a  disc  which  is  firmly  keyed  to  the  shaft.  X  shows 
the  position  of  the  crank-pin  in  its  relation  to  the  other  parts ; 
A  A  are  weights  attached  to  arms  having  their  fulcra  at  0  0; 
H H  are  coiled  springs,  attached  at  one  end  to  the  arms  at  0  0 
by  means  of  swivels,  and  at  the  other  by  means  of  adjustable  hooks, 
K K,  As  will  be  observed,  short  stub,  connecting-rods,  having 
one  end  attached  to  the  weighted  arms  and  the  other  end  to  the 


THE   engineer's  HANDY-BOOK. 


649 


cast-iron  collar,  J5,  which  is  accurately  fitted  to  the  shaft,  are 
introduced  between  the  weights  and  the  springs.  This  collar,  B, 
has  an  arm  which  extends  from  one  side  to  the  periphery  of  the 
disc,  and  which  ends  in  a  flat  weight,  G,  to  which  weights  of  the 


same  shape  may  be  attached.  On  the  opposite  side  an  ear,  /,  is 
shaped  to  receive  a  sliding-block;  close  to  the  periphery  of  the 
disc,  S S,  is  pivoted  an  arm,  E,  its  other  end  encircling  the  shaft, 
and  which  (in  consequence  of  having  an  oblong  slot)  admits 
of  a  swinging  motion  across  the  shaft;  at  its  end  opposite  the 
pivot,  beyond  the  part  encircling  the  shaft,  is  an  ear  or  boss  sus- 
taining a  steel  pin,  upon  which  pin  turns  the  sliding-block  which 
moves  in  the  ear,  I.  Upon  the  armi^  F,  is  bolted  the  eccentric, 
which  has  a  sufficient  advance  to  give  a  f  cut-ofF  when  the  gov- 
ernor is  at  rest.  The  spottings,  PP,  are  intended  for  the  fulcra 
55 


650 


THE    engineer's  HANDY-BOOK. 


of  the  weighted  arms,  in  case  it  should  be  necessary  to  run  the  en- 
gine in  the  opposite  direction. 

The  action  of  the  governor  may  be  explained  as  follows : — 
When  the  engine  is  travelling  below  speed,  the  eccentric  is  kept  in 
full  throw  by  the  tension  of  the  spiral  springs,  and  the  steam  fol- 
lows the  piston  three-fourths  of  the  stroke.  As  soon  as  the  proper 
speed  is  attained,  the  centrifugal  action  of  the  weights,  A  ^,  over- 
come the  tension  of  the  springs,  and  they  move  outwards  in  the 
direction  of  the  arrows,  thus  lengthening  the  spring.  By  means 
of  the  connecting-rods,  C  C,  the  outward  motion  of  the  weights 
gives  a  motion  round  the  shaft  to  the  collar,  B,  which  in  turn,  by 
means  of  the  ear,  G,  and  the  sliding-block  attached  to  the  arm,  E, 
gives  the  latter  an  oscillating  movement  from  its  point  of  suspen- 
sion across  the  shaft  (as  shown  by  the  arrows),  and  at  the  same 
time  to  the  eccentric,  which  is  bolted  to  it. 

The  Improyed  Circulating  Salinometer. 

The  cut  on  page  651  represents  the  Circulating  Salinometer, 

the  object  of  which  is  to  prevent  the  sputtering  or  boiling  of  the 
water  when  drawn  off  from  the  boiler  under  pressure,  and  the 
consequent  inconvenience  and  danger  of  scalding.  This  object  is 
accomplished  by  reducing  the  temperature  below  the  boiling-point 
before  it  enters  the  testing-pot.  ^  It  serves  also  to  keep  up  a  con- 
tinuous circulation,  so  that  the  degree  of  saturation  can  be  ob- 
served at  any  moment,  thus  avoiding  the  necessity  of  frequently 
drawing  off  the  water,  and  saving  the  time  which  would  be 
wasted  in  so  doing.  This  salinometer  consists  of  a  large  and 
small  pot  attached  to  the  same  bottom,  one  inside  of  the  other, 
with  a  coil  in  the  annular  space  between  the  two  pots.  This  coil 
is  connected  at  the  top  with  a  globe-valve,  and  at  the  bottom  with 
a  passage  leading  into  the  small  or  testing-cup,  which  contains  a 
hydrometer  and  thermometer,  the  latter  being  hung  by  a  spring 
hook  on  the  upper  edge  of  the  pot.  The  right-hand  globe-valve 
is  used  for  admitting  cold  water  into  the  annular  space  between 


THE  ENGINEER'S  HANDY-BOOK. 


651 


the  pots,  for  the  purpose  of  reducing  the  temperature  of  the  water 
in  its  passage  from  the  boiler  to  the 
required  degree,  so  that  it  may  rise  in 
the  testing-pot  perfectly  quiescent,  and 
is  kept  at  the  proper  height ;  and  the 
circulation  is  maintained  by  openings 
to  the  pot  near  the  top,  through  which 
it  overflows  into  the  annular  space  be- 
tween the  two  pots,  after  which  it  es- 
capes with  the  cold  water  by  the  escape- 
pipe  through  the  passage-way,  making 
but  one  connection  at  the  bottom. 
These  passages  are  situated  upon  each 
side,  right  and  left,  and,  should  they 
become  choked  by  sediment  resulting 
from  muddy  water,  they  can  be  cleaned 
out  by  disconnecting  the  escape-pipe 
and  running  a  wire  through  them. 
The  plug-cock  at  the  bottom  is  only 
used  for  emptying  the  testing-pot  when 
required,  and  has  no  communication 
with  anything  else. 

The  water  from  the  boiler  and  the 
cold  water  can  in  no  way  become 
mixed  except  by  the  bursting  of  the 
coil,  which  is  not  likely  to  happen  un- 
less it  should  be  left  full  of  water  and 
allowed  to  freeze.  The  coils  are  thor- 
oughly tested  before  they  are  put  in ; 
the  top  is  not  specially  designed  to  be 
tight,  as  nothing  can  escape  from  the 
joints  but  the  cold  water,  and  that 
only  when  the  annular  space  is  allowed 
to  become  full,  which  is  unnecessary, 
as  a  very  small  quantity  of  cold  water 


652 


THE   ENGINEER'S  HANDY-BOOK. 


will  be  sufficient  to  reduce  the  temperature  of  the  water  passing 

through  the  coil.  A  hole  is  drilled  in 
the  back  of  the  large  pot,  near  the 
top,  which  allows  the  water  to  escape 
in  case  it  should  accidentally  become 
full.  The  cold  water  is  supplied  by  a 
pipe  connected  by  a  globe-valve  to  any 
pipe  or  valve  below  the  water-line  sup- 
plying cold  water,  and  led  to  the  sali- 
nometer.  If  it  should  be  desired  to 
place  the  salinometer  above  the  out- 
side water-level,  the  cold  water  can  be 
supplied  by  some  of  the  pumps. 

In  erecting  these  salinometers,  they 
may  be  secured  to  the  boilers  or  bulk- 
head, but  when  there  are  two  or  more 
boilers,  a  very  neat  and  convenient 
arrangement  may  be  made  by  fitting 
them  close  together  on  a  plain  cast-iron 
plate  fastened  down  with  tap-bolts,  and 
with  the  pipe  for  the  cold  water  fitted 
just  above  them,  with  a  T  coupling 
and  branch  to  each  one,  the  plate  being 
secured  with  tap-bolts  in  any  conven- 
ient place  in  the  engine-room.  A 
salinometer  may  be  attached  to  each 
boiler,  and  all  of  them  supplied  with 
cold  water  from  the  same  pipe,  or  one 
may  be  connected  with  two  or  more 
boilers. 

It  is  preferable  to  have  one  con- 
nected with  each  boiler,  as  in  that  case 
the  density  of  the  water  may  be  ob- 
served in  any  boiler  independent  of 
the  others.    To  put  the  salinometer  in 


THE   engineer's   HANDY-BOOK.  653 


operation,  it  is  only  necessary  to  open  the  valve  communicating 
between  the  boiler  and  the  salinometer,  and  admit  the  water^as 
fast  as  the  overflow  will  allow  it  to  escape,  and  when  the  temper- 
ature reaches  the  required  degree,  the  communication  may  be  suf- 
ficiently closed  only  to  allow  the  necessary  circulation.  Then  the 
cold-water  valve  may  be  opened,  and,  if  the  connectiv>n  \f  ith  the 
boiler  has  considerable  length  of  pipe  to  retain  cold  wit^r,  the 
blow-ofi*  cock  may  be  opened  to  admit  of  its  escape,  and  then 
closed.  A  very  slight  opening  of  either  valve  wiJl  be  saflicient 
to  keep  up  the  circulation  and  keep  the  water  sit  the  "required 
temperature.  If  the  water  should  be  admitted  too  rapidly  from 
under  pressure,  the  agitation  of  the  water  at  the  bottom,  even 
below  the  boiling-point,  will  disturb  the  hydrometer.  When  the 
circulation  and  temperature  are  properly  adjusted,  it  will  not  re- 
quire to  be  touched  from  one  end  of  a  passage  to  another,  unless 
it  may  be  to  adjust  the  cold-water  valve  occasionally  if  any  con- 
siderable change  takes  place  in  the  temperature  of  the  water  in 
the  boiler. 

The  manipulation  and  operation  of  these  salinometers  are  very 
simple  and  satisfactory,  as  they  are  a  decided  improvement  on  any 
other  arrangement  of  the  kind  ever  heretofore  used  for  the  same 
purpose,  as,  with  one  of  them  attached  to  each  ))oiler,  the  density 
of  the  water  may  be  accurately  determined  at  any  moment,  which 
is  a  feature  of  great  importance  in  many  respects,  and  a  fact 
which  will  be  appreciated  by  those  who  have  used  other  arrange- 
ments. The  different  parts  of  the  salinometer  are  designated  as 
follows :  A,  hot-water  pot ;  K,  outlet  for  hot-water  overflow ; 
cold-water  reservoir;  H,  general  outlet;  C,  hot-water  inlet  to 
coil ;  e,  outlet  passage  from  hot-water  pot ;  2),  cold-water  inlet ;  /, 
small  po^^^p  for  hydrometer ;  /,  passage  from  coil  to  hot-water  pot ; 
Fy  outlet  for  ^old  water. 

These  salmometers  are  manufactured  by  the  Crosby  Steam 
Gauge  and  Yalve  Company,  Boston,  Ma«s« 
5^* 


664 


THE   ENGINEEB^S  HANDY-BOOK. 


Crosby's  AdjustaWe  "Pop"  Safetj -Valve. 

The  annexed  cut  represents  Crosby's  Adjustable  "Pop"' 
Safety-Valve. — Its  mechanism  may  be  explained  as  follows :  The 
valve  proper,  B  JS,  rests  upon  two  flat  annular  seats,  V  V  and 

W  W,  on  the  same  plane,  and 
held  down  against  the  pressure 
of  steam  by  the  steel  spiral  spring, 
S,  The  tension  of  this  spring  is 
caused  by  screwing  down  the 
threaded  bolt,  L,  at  the  top  of 
the  cylinder,  K.  The  area  con- 
tained between  the  seats,  TTand 
Vy  is  what  the  steam-pressure  acts 
upon,  ordinarily,  to  overcome  the 
resistance  of  the  spring.  The 
area  contained  within  the  smaller 
seat,  W  Wy  'is  not  acted  upon  at 
all  until  the  valve  opens.  The 
large  seat,  F  F,  is  formed  on  the 
upper  edge  of  the  shell  or  body 
of  the  valve,  A  A.  The  small 
seat,  W  W,  is  formed  on  the  up- 
per edge  of  a  cylindrical  cham- 
ber or  well,  C  C,  which  is  situated 
in  the  centre  of  the  shell  or  body 
of  the  valve,  and  is  held  in  its 
place  by  four  arms,  D  Z>,  radiat- 
ing horizontally  at  right  angles 
to  each  other,  and  connecting  it 
with  the  body  or  shell  of  the 
valve.  These  arms  are  hollow 
and  form  four  passages,  E  E,  for 
the  escape  of  the  steam  or  other  fluid  from  the  well  into  the  air 
when  the  valve  is  open.    This  well  is  deepened,  so  as  to  allow  the 


•u.  a/ncMNoaoAf  sc. 


THE   ENGINEEr\s  HANDY-ROOK, 


655 


wings,  X Xy  of  the  valve  proper  to  project  down  into  it  far  enough 
to  act  as  guides.  The  area  of  the  apertures  at  the  outer  ends  of 
the  passages  through  the  arms  is  reduced  more  or  less  at  will  by 
screwing  up  or  down  the  adjustable  ring,  0  G. 

Action  of  the  **Pop"  Safety-Valve  when  under  Pressure. — 
When  the  pressure  under  the  valve  is  within  about  one  pound  of  the 
maximum  pressure  required,  the  valve  will  open  slightly,  and  the 
steam  will  escape  under  the  larger  seat  into  the  cylinder  surround- 
ing the  spring,  and  thence  into  the  air.  The  steam  is  also  forced 
under  the  smaller  seat  into  the  well,  and  thence,  through  the  pas- 
sages in  the  arms,  into  the  air.  As  soon  as  the  pressure  attains 
the  exact  maximum  point,  the  valve  will  be  lifted  so  high  as  to 
force  the  steam  into  the  well  faster  than  it  can  escape  through  the 
apertures  in  the  arms.  A  pressure  will  then  accumulate  under 
the  inner  seat,  which  will  be  in  excess  of  what  was  required  to 
overcome  the  increasing  resistance  offered  by  the  spring,  and,  act- 
ing upon  the  additional  area  presented,  at  once  forces  the  valve 
wide  open,  and  rapidly  relieves  the  boiler.  This  pressure  under 
the  inner  seat  is  of  itself  differential.  The  valve  then  at  once 
slowly  settles  down,  and  the  pressure  under  the  inner  seat  as 
slowly  diminishes.  This  action  continues  until  the  area  of  the 
opening  under  the  smaller  or  innep  seat  is  less  than  the  area  of 
the  apertures  in  the  arms  for  the  escape  of  the  steam ;  the  pressure 
then  ceases  and  the  valve  promptly  closes.  The  point  of  opening 
can  be  readily  changed  while  under  steam  by  screwing  the  threaded 
bolt  at  the  top  of  the  cylinder  either  up  or  down,  and  the  point 
of  closing  is  as  easily  adjusted  by  screwing  up  or  down  the  ring 
surrounding  the  outside  body  or  shell  of  the  valve. 

This  valve  is  automatic,  certain  in  its  action,  prompt  in  open- 
ing and  closing  at  the  required  points  of  pressure,  and  can  be  fully 
relied  upon  to  relieve  the  boiler  under  all  circumstances.  Expe- 
rience and  use  have  confirmed  the  following  claims  for  it,  namely, 
opens  precisely  at  fixed  working  pressure ;  discharges  all  excess 
of  steam  above  fixed  working  pressure ;  reduces  the  pressure  rap- 
idly upon  opening ;  closes  with  the  least  possible  loss  of  steam ; 


656 


THE   ENGINEER^'S  HANDY-BOOK. 


the  limits  of  pressure  within  which  the  valve  will  open  and  clpse 
are  adjustable ;  uniform  in  action  at  different  pressures ;  simple  in 
arrangement,  and  easily  connected  and  adjusted ;  does  not  deteri- 
orate under  continued  use ;  never  sticks  on  seat ;  makes  compara- 
tively little  noise  in  discharging;  occupies  less  room  than  any 
safety-valve.  These  valves  are  made  to  correspond  with  the  re- 
quirements of,  and  are  used  on,  locomotive,  portable,  steamboat, 
stationary,  and  steam  fire-engine  boilers,  and  for  other  pur- 
poses. Each  of  these  valves  is  tested  under  steam  pressure,  and 
set  to  open  at  the  exact  point  of  pressure  desired,  and  is  ad- 
justed to  close  at  about  two  pounds  reduction.  Both  of  these 
points  may  be  readily  changed  by  the  operator  without  removing 
the  valve  from  the  boiler  or  reducing  steam.  Any  person  of  ordi- 
nary intelligence  will  readily  understand  the  principle  and  opera- 
tion of  these  valves. 


The  Improyed  Planimeter. 

The  above  cut  represents  the  improved  Planimeter  as  espe- 
cially adapted  for  ascertaining,  from  the  indicator  diagram,  the 
average  pressure  in  the  steam-engine  cylinder,  and  also  for  meas- 
uring the  superficial  contents  of  regular  or  irregular  plain  sur- 
faces. It  is  claimed  to  have  the  advantages  over  any  other  in  use, 
in  being  supplied  with  a  supplementary  wheel,  with  a  graduated 
plate,  marked  with  figures  representing  ten  times  the  value  of  the 
figure  on  the  roller-wheel,  thus  saving  the  care  and  trouble  inci- 
dental to  the  use  of  the  other  single-wheel  instruments,  and  in  giv- 
ing the  average  height  of  the  indicator  diagram  in  one-fortieth  of 


THE   engineer's  IIANDY-BOOK. 


657 


an  inch  (instead  of  the  area),  which,  multiplied  by  a  factor  repre- 
senting the  scale  or  number  of  the  spring  used,  gives  the  average 
pressure  in  pounds,  without  the  long  process  and  troub^  of  meas- 
uring the  length  of  the  diagram,  dividing  it  into  the  area,  and 
then  multiplying  by  the  vertical  scale. 

It  is  also  adapted  for  measuring  the  superficial  contents  of  reg- 
ular or  irregular  plain  surfaces,  and  representing  the  contents 
either  in  millimeters,  inches,  feet,  perches,  or  acres,  as  the  opera- 
tor may  desire,  by  adjusting  the  sliding-bar.  In  the  case  of  indi- 
cator diagrams,  if  the  Crosby  Indicator  be  used,  the  process  of 
finding  the  area  of  the  diagram  is  simplified,  as  the  springs  used 
are  of  such  scales  (mostly  multiples  of  four)  that,  instead  of  the 
long  process  formerly  used,  the  mean  pressure  is  obtained  by  sim- 
ply multiplying  by  a  factor  corresponding  to  the  scale  used,  as 
follows : 

Spring   8      12      16      20      24      30      32      40  48 

Factor   02      0*3      0*4      0*5      06    075      08      I'O  1°4 

The  numbers  engraved  upon  the  sliding-bar,  A,  serve  for  the 
calculation  of  the  contents  of  surfaces,  for  which  special  instruc- 
tions are  required.  The  arms  of  these  planimeters  are  made  hol- 
low and  composed  of  the  best  grade  of  German  silver,  the  whole 
instrument  being  made  with  great  precision,  accuracy,  and  skill. 
They  are  manufactured  by  the  Crosby  Steam  Gauge  and  Valve 
Company,  Boston,  Mass.  The  same  firm  makes  two  other  styles 
of  planimeters,  one  corresponding  with  the  common  instrument  in 
use,  which  has  only  one  wheel,  as  shown  on  page  323,  and  another 
similar  to  it,  having  two  wheels. 

Crosby's  Improyed  Steam-Pressure,  Hydraulic,  Combina- 
tion, Vacuum,  and  Self-Testing  Gauges. 

Steam  Gauges. — About  the  year  1849,  Eugene  Bourdon,  of 
France,  discovered  that  the  free  end  or  ends  of  a  flattened  me- 
tallic tube  possessed  of  sufiicient  elasticity  for  use  as  a  spring, 
would  move  when  pressure  was  exerted  through  the  medium  of  a 

2R 


658 


THE  engineer's  HANDY-BOOK, 


Exterior  View  of  Crosby's  Steam 
Gaugeo 


fluid  applied  externally  or  internally;  that  the  motion  was 
in  direct  proportion  to  the  pressure  applied ;  and  that  when  the 

pressure  was  removed  they 
would  assume  their  former 
position.  From  this  circum- 
stance, he  conceived  the  idea 
of  a  new  pressure  gauge,  in 
which  the  bent  tube  should 
be  the  main  spring  or  means 
of  motioUc  But,  though  it 
was  generally  conceded  at 
that  time  that  the  hollow 
tube  spring  gauge,  as  invent- 
ed by  Bourdon,  excelled  in 
delicacy  and  sensitiveness 
any  previous  mechanical  ar- 
rangement employed  for  that 
purpose,  nevertheless,  it  was  demonstrated  by  experience  that  such 
a  device,  owing  to  its  pecu- 
liar construction,  was  not  well 
adapted  for  all  the  purposes  for 
which  pressure  gauges  are  em- 
ployed, as,  in  consequence  of 
being  held  only  at  one  end,  it 
would  vibrate  from  a  sudden 
shock  or  slight  change  of  press- 
ure, thus  causing  the  pointer  to 
oscillate  on  the  dial-plate,  in- 
ducing friction  and  wear,  and 
rendering  the  indications  of 
the  gauge  uncertain  and  delu- 
sive. Besides,  the  dip  of  such 
a  spring  caused  it  to  retain  a 
portion  of  the  water  condensed  in  it,  thus  rendering  it  liable  to 
burst  in  cold  weather,  to  be  strained  by  freezing,  and  lose  its  tension. 


Interior  View  of  the  Original 
Bourdon  Steam  Gauge. 


THE   engineer's  HANDY-BOOK. 


659 


To  overcome  these  defects,  numerous  devices  have  been 
suggested  and  tried,  but  they 
almost  invariably  embodied  the 
same  defects  as  those  above 
mentioned,  and  were  subject  to 
the  same  errors,  the  gravest  of 
which  arose  from  the  straight- 
ening or  setting  of  the  springs. 
Steam  users  are  more  indebted 
to  George  H.  Crosby  for  reme- 
dying the  foregoing  defects  in 
pressure  gauges,  and  for  the  pro- 
duction of  a  perfectly  reliable 
steam  gauge,  than  to  any  one 
previous  to  his  time,  as  he  dis- 
covered, by  observation  and  ex- 
periment, that  only  the  horizontal  motion  of  the  free  ends  of  the 
springs  or  tubes,  while  under  varying  pressure,  had  been  used 
heretofore,  and  that  they  had  a  perpendicular  or  upward  action, 
as  well,  when  the  springs  were  of  proper  length  and  shape,  and 
that  by  uniting  these  motions  by  proper  mechanism,  it  could  all 
be  transmitted  to  the  pointer.  In  accomplishing  this,  he  discov- 
ered that  a  firmer  and  stifier  spring  than  any  heretofore  used  for 
the  same  pressure  was  an  absolute  necessity.  And  as  a  result, 
no  pressure  over  that  indicated  by  the  pointer  on  the  dial  will 
afiect  their  original  elasticity,  and  vibration  of  the  pointer  under 
varying  pressures  is  obviated ;  besides,  in  consequence  of  the  spring 
being  held  at  the  lowest  points,  they  have  no  dip,  which  arrange- 
ment admits  of  the  water  returning  to  the  siphon,  thus  preventing 
freezing.  Thus  it  would  seem  that,  while  the  Crosby  gauges  em- 
brace all  the  desirable  points  in  the  original  Bourdon  gauge,  they 
also  embody  many  others  which  have  been  demonstrated  by  expe- 
rience to  be  absolute  necessities  in  the  construction  of  an  accurate^ 
reliable,  and  serviceable  steam  gauge. 


Interior  View  of  Crosby's 
Steam  Gauge. 


660 


THE   engineer's  HANDY-BOOK. 


Crosby's  Self-Taeting'  Steam  Gauge. 


Self- Testing  Steam  Gauges. — This  class  of  gauges  is  of  great 
importaDce,  convenience,  and  utility,  as  the  engineer  in  charge  can 
always  ascertain  whether  his  gauge  is  correct  or  not  by  observing 

the  following  instructions : 
Set  off  all  pressure  that  may 
be  on  the  gauge,  after  which 
the  pointer  will  fall  to  zero ; 
then  unscrew  the  plug  on  the 
left-hand  side,  which  uncov- 
ers the  hook.  To  this  hook 
hang  the  first  weight  by  the 
spindle.  This  is  marked  by 
a  certain  number,  and  the 
pointer  should  travel  at  once 
to  the  corresponding  number 
on  the  dial,  if  correct  at  this 
point.  But  if  the  pointer 
stands  below  or  above  this 
number,  it  will  indicate  just  how  much  the  gauge  is  "out,"  and  in 
which  direction.  Proceed  by 
adding  the  next  higher  num- 
bered weight,  and  continue  as 
before. 

Vacuum  Gauges. — The  con- 
ditions under  which  vacuum 
gauges  act  are  the  reverse  of 
steam  gauges,  as,  in  the  vacu- 
um gauge,  the  interior  of  the 
tube  is  influenced  by  the  vacu- 
um, while  its  exterior  is  ex- 
posed to  the  action  of  the  at- 
mosphere. These  gauges  are 
manufactured ,  by  the  Crosby 
Steam  Gauge  and  Valve  Company,  Boston,  Mass.,  and  are  all 
tested  by  a  mercury  column  before  being  put  in  use. 


Crosby's  Vacuum  Gauge. 


56 


THE   engineer's   HANDY-BOOK.  663 

The  Atlas  Corliss  Engine. 

The  cuts  on  pages  661,  662,  show  a  front  and  back  view  of 
the  Atlas  Corliss  engine.  As  will  be  observed,  the  frame  is  of  the 
girder  pattern ;  a  form  which  has  been  more  extensively  copied, 
for  the  past  twenty  years,  by  engineers  and  steam-engine  builders 
both  in  this  country  and  Europe,  than  any  other.  Though  a  Cor- 
liss engine  in  every  respect,  it  differs  from  others  of  the  same  type 
in  many  very  important  features ;  one  of  which  is,  that  the  main 
frame,  hind  leg,  and  main-bearing  are  cast  in  one  solid  piece, 
which  is  not  generally  the  case  with  other  Corliss  engines,  as,  in 
most  instances,  the  main-bearing  and  its  supports  are  cast  sepa- 
rately, and  bolted  to  the  frame ;  another  is,  that  the  horizontal 
section  of  the  frame  is  deeper  and  heavier  than  in  most  Corliss 
engines,  while  a  deep  rib,  running  to  the  base  of  the  legs,  insures 
additional  rigidity  and  stiffness.  The  frame,  as  in  the  case  of  all 
engines  of  the  Corliss  type,  is  faced  up  at  the  front  end,  to  receive 
the  cylinder,  which  rests  on  a  pedestal  of  ample  proportions.  In 
consequence  of  the  large  metal  surface  brought  in  contact  with 
the  foundation,  the  weight  of  the  engine  is  more  uniformly  distrib- 
uted, and  the  jar,  which  is  so  detrimental  to  the  stability  of  many 
types  of  engines,  is  entirely  obviated. 

While  the  steam-  and  exhaust-valves  and  the  cut-off  arrange- 
ments are  essentially  the  same  as  in  most  Corliss  engines,  the 
mechanism  which  works  the  valves  and  controls  the  cut-off,  is 
entirely  different.  In  the  ordinary  Corliss  engine,  only  one  ec- 
centric is  employed  to  operate  the  steam-  and  exhaust-valves, 
through  the  medium  of  a  wrist-plate,  which  must  be  so  connected 
with  the  eccentric,  as  to  change  the  direction  of  its  motion  at  the 
proper  time  for  opening  and  closing  the  steam-  and  exhaust- 
valves.  To  accomplish  this  object,  the  eccentric  must  be  placed 
nearly  at  a  right  angle  with  the  crank ;  in  consequence  of  which 
its  direction  changes  at  about  half-stroke ;  the  result  of  which  is, 
that  the  cut-off  is  limited  to  the  preceding  portion  of  the  stroke, 
as  the  clutch  must  be  detached  during  the  forward  motion.  In 


664  THE   ENGINEER'S  HANDY-BOOK. 

the  Atlas  engine,  this  difficulty  is  remedied,  as  two  eccentrics  are 
used  —  one  for  the  steam-  and  the  other  for  the  exhaust-yalveSj 
each  of  which  is  set  independently,  for  the  most  accurate  per- 
formance of  its  own  work.  The  exhaust  eccentric  has  nearly  the 
same  angular  position  as  the  single  eccentric  in  ordinary  Corliss 
engines.  The  cut-off  eccentric  is  placed  nearly  90  degrees  behind 
it,  and  therefore  does  not  change  the  direction  of  the  cut-off  clutch, 
until  a  correspondingly  later  period  in  the  stroke  is  reached,  which 
is  a  very  important  feature  in  itself 

The  manner  in  which  the  eccentrics  receive  their  motion  is  dif- 
ferent from  that  generally  employed,  as,  instead  of  being  rotated 
on  the  crank-shaft,  they  are  placed  on  a  supplementary  or  counter 
shaft,  which  has  the  same  motion  as  the  main  shaft,  and  is  situated 
directly  under  the.  cylinder  end  of  the  frame.  This  eccentric 
shaft  is  operated  through  the  medium  of  gears  from  the  main 
shaft,  through  a  side  shaft,  which  is  located  directly  under  the 
horizontal  rib  of  the  frame.  The  side  shaft  also  operates  the  gov- 
ernor, thus  dispensing  with  the  governor-belt  and  its  necessary 
risk  and  uncertainty.  The  governor  is  of  the  "Portei*"  type, 
which  has  been  successfully  applied  to  engines  on  which  most 
other  governors  have  failed  to  give  satisfactory  results.  This  is 
due  to  the  fact,  that  the  heavy  centre  weight  gives  the  constant 
force  of  gravity  acting  downwards ;  while  the  centrifugal  force  of 
the  rapidly  revolving  balls  is  the  variable  force,  and  acts  upwards 
through  the  joints  of  the  governor;  the  result  of  which  is,  that  the 
governor  rises  or  falls,  as  the  variable  force  is  greater  or  less  than 
the  constant  force.  It  is  very  powerful  and  sensitive,  and  holds 
the  engine  in  perfect  control  under  the  most  varying  circum- 
stances of  load  and  pressure.  It  is  also  provided  with  an  auto- 
matic stop,  which  becomes  operative  in  case  of  accident. 

The  valves  and  cut-off  mechanism  are  essentially  the  same  in 
the  Atlas  as  in  most  other  Corliss  engines,  as  may  be  seen  in 
the  cuts  on  pages  284,  285. 

A  is  the  valve-stem,  as  shown  in  Fig.  1.  £  is  a  bell-crank  fast- 
ened to  the  valve-stem,  by  which  motion  is  communicated  to  the 


THE   engineer's  HANDY-BOOK. 


665 


valve.  C  is  the  cut-ofF  clutch,  which  is  made  of  gun-metal  and 
faced  with  hardened  steel.  D  is  a  case-hardened  block,  having  a 
large  bearing  in  the  bell-crank,  B,  which  allows  it  to  adapt  itself 
freely  to  any  angular  position.  This  block  is  virtually  a  part  of 
the  bell-crank,  and  contains  a  hole  at  right  angles  to  the  axis 
of  its  bearing,  through  which  the  small  end  of  the  rod,  F,  which 


Figr.  1. 


carries  the  cut-off  clutch,  is  passed,  and  receives  its  motion  from 
the  cut-off  eccentric  by  means  of  a  rocking-plate  on  the  side  of  the 
cylinder.  G  is  the  dash-pot  rod,  to  which  a  weight  is  attached, 
for  the  purpose  of  closing  the  valves  promptly  when  the  cut-off 
is  effected.  H  is  the  governor-rod  ;  it  varies  the  augulr.r  position 
of  the  governor-toe,  jST,  as  the  governor  rises  and  falls,  and 
56* 


666 


THE   engineer's  HANDY-BOOK. 


determines  the  time  of  cut-ofF.  K  is  the  governor-toe,  and  is  sup- 
ported on  a  bushing  concentric  with  the  valve-stem.  The  cut-off 
occurs  when  the  governor-toe,  Ky  depresses  the  cut-off  clutch,  (7,  suf- 
ficiently to  detach  it  at  the  point,  from  the  bell-crank,  5,  allow- 
ing the  unsupported  weight  of  the  dash-pot  to  close  the  valve  by 
its  fall. 

A  cross -section  of  the  cylinder  through  the  steam-  and  exhaust- 
ports  is  shown  in  Fig.  2. 


Fig.  2. 

A  is  the  bell-crank,  connected  by  the  cut-off  clutch  directly  to 
the  rocking-plate.  B  is  the  stufBng-box,  which  has  a  very  long 
bearing  between  the  ground-joints  of  the  collar  and  the  gland  at 
the  outside.  C  is  an  out-board  bearing  fitted  with  a  bushing,  the 
inside  of  which  forms  a  bearing,  the  cut-off  toe  of  the  governor 


THE   engineer's  HANDY-BOOK. 


667 


being  carried  on  its  outer  surface.  The  advantage  of  this  arrange- 
ment is,  that  it  prevents  the  valve-stems  from  springing,  which 
would  have  a  tendency  to  increase  their  friction,  and  cause  them 
to  wear  out  of  round  ;  while,  in  consequence  of  the  brackets  being 
hollow,  they  form  a  receptacle  for  the  drips  from  the  valve-stem, 
stuffing-boxes,  and  insure  perfect  drainage.  There  are  many 
points  of  excellence  to  be  noticed  in  the  design  and  construction 
of  these  engines,  among  which  are  simplicity  of  design,  convenient 
arrangements  for  accurate  adjustment  of  the  different  parts,  and 
independent  steam-  and  exhaust-valve  motions.  The  cross-head 
bearings  are  flat,  and  so  arranged  that  they  may  be  repaired  or 
renewed  at  short  notice  and  trifling  expense.  Besides,  the  cross- 
head  wrist-pin  is  placed  both  in  the  horizontal  and  vertical  centre 
lines  of  the  bearing  surfaces,  thus  relieving  the  cross-head  of  the 
excessive  weight  and  severe  strain  incident  to  an  overhanging 
connection. 

The  Atlas  Corliss  engines  are  built  of  excellent  material, 
thoroughly  fitted,  and  tastefully  finished.  The  bearings  for  the 
rubbing,  reciprocating,  and  revolving  surfaces  are  ample,  thus 
preventing  the  possibility  of  rapid  wear  and  the  necessity  of  ex- 
pensive repairs.  The  fly-wheels  are  turned  on  the  face  and  sides, 
and  accurately  balanced,  which  insures  smooth  running ;  while  the 
cylinders  are  covered  with  "asbestos"  and  cast-iron  lagging,  which 
prevents  condensation  and  insures  economy.  The  steam-piston 
packing  used  is  Babbit  &  Harris's  patent  (an  illustration  of  which 
may  be  seen  on  page  167),  which  has  been  generally  adopted  by 
the  builders  of  the  best  class  of  steam-engines  in  the  country,  and 
has  the  reputation  of  giving  entire  satisfaction. 

The  Atlas  engines  are  built,  both  condensing  and  non-condens- 
ing, of  any  power  to  meet  the  requirements  of  purchasers,  and  for 
whatever  purpose  employed,  whether  for  milling,  manufacturing, 
or  pumping,  ha\e  the  reputation  of  giving  entire  satisfiiction. 
They  are  manufactured  at  the  Atlas  Corliss  Engine  Works,  In- 
dianapolis, Indiana. 


668 


THE   ENGINEER'S  HANDY-BOOK. 


Questions, 

THE  ANSWERS  TO  WHICH  WILI    BE  FOUND  IN  THE  TEXT. 

What  is  acceleration  ? 
Define  the  term  affinity. 
What  constitutes  an  angl<j? 

Explain  the  principle  embraced  in  the  use  of  axles. 

Give  the  meaning  of  the  term  attraction. 

What  is  meant  by  capillary  attractions? 

Define  the  terms  gravity  and  centre  of  gravity. 

Give  the  meaning  of  the  terms  adhesion  and  cohesion. 

Under  what  two  heads  may  elastic  fluids  be  classified? 

Define  the  term  elasticity. 

Has  the  term  energy  any  definite  meaning  when  applied  to 

mechanics? 

What  is  force? 

Define  the  term  focus  as  used  in  geometry. 
What  is  meant  by  the  term  friction  ? 

Give  the  meaning  of  the  terms  hydrodynamics,  hydrostatics,  and 
hydraulics. 

Explain  the  formation  of  the  hyperbola. 

Define  the  term  impact. 

What  is  meant  by  the  term  impenetrability  ? 


THE  engineer\s  JIANDY-ROOK.  669 

Define  the  term  impetus,  as  applied  to  mechanics. 

What  is  meant  by  the  incidence,  as  applied  to  mechanics? 

Explain  the  meaning  of  the  term  inclination. 

To  what  class  of  the  mechanical  powers  does  the  inclined  plane 
belong  ? 

What  is  the  meaning  of  the  term  inertia? 
Under  what  three  classes  may  levers  be  divided? 
Give  the  definition  of  the  term  machine. 

What  physical  elements  are  embraced  under  the  head  of  me- 
chanics ?  ^ 

What  is  meant  by  the  modulus  of  the  elasticity  of  any  sub- 
stance ? 

Give  the  meaning  of  the  term  momentum. 
What  is  meant  by  motion,  as  applied  to  mechanics? 
Enumerate  the  different  kinds  of  motions. 
Define  the  centre  of  oscillation. 

Explain  the  mechanical  principles  represented  in  the  vibration 
of  the  pendulum. 

Define  the  centre  of  percussion. 

Why  is  perpetual  motion  an  impossibility? 

Explain  the  meaning  of  the  term  pneumatics. 

Of  what  two  forces  is  power  the  product? 

What  is  the  difference  between  pressure  and  weight? 


670  THE   ENGINEER'S  HANDY-BOOK. 

What  kind  of  machines  may  be  termed  prime  movers  ? 

What  is  the  mechanical  principle  involved  in  the  use  of  the 
pulley  ? 

To  which  of  the  mechanical  powers  is  the  screw  most  nearly 
allied? 

Give  the  meaning  of  the  term  resilience. 
Define  the  science  of  statics. 

What  is  meant  by  strength,  when  applied  to  mechanics? 

Enumerate  the  different  kinds  of  strength. 

Give  the  meaning  of  the  word  tools. 

Define  the  term  torsion. 

What  is  meant  by  the  term  velocity? 

What  is  understood  by  the  term  weight? 

Under  which  of  the  mechanical  powers  may  the  wheel  and 
axle  be  classed? 

What  mechanical  principles  are  embodied  in  the  wedge? 

Give  the  atomic  weights  and  chemical  equivalents  of  the  dif- 
ferent metals  in  use  at  the  present  day. 

Which  is  the  most  useful  metal  ? 

Give  the  weight  of  a  cubic  foot  of  wrought-  or  cast-iron. 

Give  the  component  parts  of  cast-iron. 

Of  what  two  elements  is  steel  composed  ? 

Give  the  heat-conducting  properties  of  copper,  brass,  cast-  and 
wrought-iron. 


THE   engineer's   HANDY-BOOK.  671 

Give  the  tensile  strength  of  copper,  brass,  gun-metal,  wrought- 
and  cast-iron. 

Give  the  proportions  of  carbon  in  the  various  grades  of  iron 
and  steel. 

Give  the  different  proportions  of  the  metals  which  form  the 
basis  of  brass,  Muntz  metal,  gun-metal.  Babbitt  metal,  and  bronze 
alloy. 

Give  the  composition  of  fusible  metal  which  melts  at  a  tem- 
perature of  212°  Fah. 

Give  the  rule  for  finding  the  approximate  weight  of  iron  cast- 
ings from  the  weight  of  the  pattern. 

Give  the  shrinkage  various  metals  undergo  in  the  process  of 
casting. 

Give  the  weight  and  bulk  of  several  substances  in  cubic  feet, 
pounds,  and  tons. 

Give  the  extension  of  wrought-  and  cast-iron  at  various  tem- 
peratures. 

Does  wrought-iron  increase  in  heat  up  to  a  certain  tempera- 
ture? 

Is  the  tensile  strength  of  copper  increased  by  the  application 
of  heat? 

Give  the  composition  of  a  good  non-conductor  for  preventiug 
radiation  of  heat  in  steam-boilers,  cylinders,  pipes,  etc. 

Give  the  component  parts  of  a  good  durable  cement  for  steam- 
joints. 

What  advantages  does  belting  possess  over  cog-gearing,  and 

vice  versdt 


672  THE   ENGINEER'S  HANDY-BOOK. 

From  what  principle  do  belts  derive  their  power  to  transmit  . 
motion  ? 

What  are  the  necessary  characteristics  of  good  belting? 

What  conditions  are  necessary  to  obtain  the  greatest  percentage 
of  power  from  any  belt  ? 

What  advantages  have  double  and  single  belts,  and  vice  versd^ 

How  would  you  test  the  quality  of  belting? 

How  would  you  proceed  to  make  belts  run  on  the  centre  of 
pulleys  ? 

What  are  the  advantages  of  rubber  belts  over  leather,  and  vice 
versa  ? 

Give  the  rule  for  finding  the  length  of  a  belt. 

Give  the  rule  for  finding  the  number  of  horse-power  a  belt  can 
transmit. 

Give  the  rule  for  finding  the  change  in  length  in  a  belt  when 
one  of  the  pulleys  is  changed. 

Explain  the  most  practicable  method  of  putting  on  belts. 

State  the  precautions  to  prevent  accidents  when  throwing  on 
or  taking  ofi*  belts. 

Give  the  rule§  for  finding  the  size  of  pulleys  for  any  required 
speed. 


A.m.  or  Aba,  264. 
Acceleration,  587. 

Accidents  by  revolving  shaftSj  how  to 
prevent,  643. 

Actual  extension  of  wrought-iron  at  va- 
rious temperatures,  table  showing, 
621. 

Adhesive    cement,   how  to   make  a 

good,  636. 
Adiabatic,  263. 

Adj  uncts  of  steam-boiler,  technical  terms 

applied  to,  476. 
Adjustable  cut-off,  227. 
Adj  ustments,  most  accurate  methods  of 

testing,  274. 
Admission,  263. 
Affinity,  587. 

Aggregate  strain  caused  by  pressure  of 
steam  on  shells  of  boilers,  rule  for 
finding,  451. 

Mr,  496. 

A-ir-casing,  476. 

Air-pump  and  condenser,  independent, 
345. 

Air-pump  bucket,  356,  357. 

double-acting,  356. 

pet-cock  or  valve,  357. 

piston,  356. 

plunger,  356. 

rods,  357. 

ship's  side,  357. 

trunk,  356. 
Air-pumps,  353. 

capacity,  354. 

independent,  355. 

vertical,  354. 
Air- valve,  355. 
Alkali,  534. 
Alloy,  bronze,  616. 
"Alloys  and  compositions,  616. 

metals,  612. 
■Altitude,  apparent,  376. 

57  2 


Altitude,  meridian,  376. 
observed,  376. 

of  highest  mountains  in  the  world,  500. 
true,  376. 

Altitudes  above  sea-level,  table  of,  498. 
Ammonia,  534. 
Amplitude,  376. 
Analysis,  534. 

chemical*  506. 

of  diagrams,  271. 

of  sea-water,  457. 
Angle,  587. 

.  irons,  476. 
Angular  advance  of  eccentric,  183. 
Anthracite  coal,  composition  of,  511. 
Apparent  altitude,  376. 

time,  381. 

Application  of  theoretic  curves.  280. 
Appointments  as  cadet  engineers  in  the 

U.  S.  Navy,  necessary  qualifications 

of  candidates  applying  for,  40. 
Approximate  weight  of  iron  castings 

from  patterns,  rule  for  finding,  619. 
Areas  of  circles,  536. 
Arithmetic,  decimal,  560. 

examination  in,  43. 
A.scension,  right,  381. 
Assistant  engineer,  first,  58. 

in  the  U.  S.  re\enue  cutter  service, 

standard  of  examination  for,  58. 
Astronomical  time,  381. 
Asymptote,  263. 
Atlas  Corliss  engine,  6C3. 
Atmosphere,  4%. 
Atom,  534. 

Atoms  and  molecules,  566. 
Attraction,  588. 

capillary,  589. 
Augmentation,  381. 
Automatic  cut-off  engine,  Brown,  88. 

Buckeye,  the,  488. 

Douglass,  the,  159. 
S  673 


674 


INDEX. 


Automatic  cut-off  engine,  Fitch  burg 
Steam-Engine  Company's,  647. 
Putnam  Machine  Company's,  138. 
Watertown,  the,  194. 
Wheeloclv,  the,  214. 
Woodbury,  Booth  &  Pry  or,  52. 
Wright's,  38. 
Automatic   cut-off  engines,  diagrams 
taken  from,  278. 
high-pressure  engine,  the  Greene,  150. 
high-pressure  engine,  the  Woodbury  & 
Beach.  124. 
Automatic  cut-off  and  throttling  engines, 
130. 

valve-gear,  227. 
Average  crushing  load  of  different  ma- 
terials, table  showing,  617. 
Axle,  588. 

and  wheel,  the,  611. 
Azimuth,  376. 

• 

Babbitt's  metal,  616. 
Back  eccentric,  183. 

Balance-engine,  Well's  two-piston,  232. 

valves,  228. 
Bank  fires,  462. 
Barometer,  the,  364. 
Bases,  534. 

Bearings,  cross-head,  181. 
Bed -plates  and  housings.  163. 
Bell-signals,  marine,  390. 
Belt,  how  to  put  on  a,  644. 
Belting,  637. 

Belts,  rubber  and  leather,  642. 
Black  finish  for  brass,  619. 
Blast-pipe,  462. 
Blow -oft*  cocks,  462. 
Boiler  materials,  480. 

plates,  practical  limits  to  thickness  of, 
485. 

stays,  453. 

Boilers,  technical  terms  employed  in  re- 
lation to,  462. 
Boiling-point,  503. 

for  fresh  water  at  different  altitudes 

above  sea-level,  table  showing.  520. 
of  salt  water  at  different  degrees  of 
density,  when  barometer  stands  at 
30  inches,  table  showing,  362. 
Bolts,  cylinder-head,  166. 

stay,  454. 
Bonnet,  160. 
Boss  of  crank,  185. 
Bourdon  spring  steam-gauge.  370. 


Brass  and  glass,  cement  for,  G37. 

black  finish  for,  619. 

castings,  lacquer  for,  619. 
Brasses,  160. 

Breaking-strain  of  iron  and  copper  stay- 
bolts,  table  showing,  455. 
Bronze  alloy,  616. 

Brown  automatic  cut-off  steam-engine,  88, 
Bucket,  air-pump,  356,  357. 
Buckeye  automatic  cut-off  engine,  488. 
Bursting-pressure  of  cylindrical  boilers 

with  riveted  seam?,  rule  for  finding, 

448. 

steam-boilers,  448.  * 

Cadet  ertgineers  in  the  U.  S.  Navy,  40. 
Calcination,  534. 
Calking,  463. 

Candidates  applying  for  appointments 
as  cadet  engineers  in  the  U.  S.  Navy, 
necessary  qualifications  of,  40. 
examination  of,  40. 

for  the  U.  S.  revenue  service,  qualifica- 
tions of,  57. 
Capacity  of  air-pumps.  354. 

of  cisterns  and  tanks,  table  showing, 
521. 

in  gallons  for  each  10-inch  depth,  table 
showing,  523. 

unit  of.  563. 
Capillary  attraction,  589. 
Carbon,  532. 
Cards,  indicator,  262. 
Care  and  management  of  steam-boilers, 
instructions  for,  478. 

of  steam-engines,  instructions  for,  235. 
Causes  of  knocking  in  steam-engines,  153. 
Celestial  object,  hour-angle  of  a,  378. 
Cement  for  brass  and  glass,  637. 

fastening  leather  to  iron,  china,  or 
glass,  636. 

leather,  636. 

leather  belting,  636.' 

rubber  belting,  637. 

rust-joints,  635. 

steam-joints  and  patching  steam-boil- 
ers, 634. 
stone  or  marble,  637. 
Central,  mechanical,   and  dynamical 

forces,  definition  of,  587. 
Centre  of  gravity,  589. 
gyration,  593. 
oscillation,  603. 
Charcoal,  533. 


IND 

Check  chamber,  476. 

valve,  476. 
Chemical  analysis,  506. 

properties  of  coal,  504. 
Chimneys,  draught  in,  469. 
Cipher,  the,  542. 
Circle,  valve,  218, 
Circles,  areas  of,  536. 
Circular-savrs,  speed  of,  632. 
Circulating-pump,   independent  ma- 
rine, 358. 
Civil  time,  381. 
Clearance,  264. 

the  term,  122. 
Clipper  injector,  the,  426. 

table  of  capacities  of,  428. 
Coefficients  of  friction  between  plane 

surfaces,  table  of,  633. 
Cohesion,  589. 

Coil  of  belting,  how  to  measure,  644. 
Collapsing-pressure  of  boiler- flues,  rule 

for  finding,  452. 
Combination,  534. 
Combustion,  510. 

spontaneous,  512. 
Common  and  decimal  fractions,  table  of, 

561. 

Comparative  efficiency  of  screw-propel- 
ler and  paddle-wheel,  399. 

value  of  different  kinds  of  wood  for 
fuel,  505. 
Compass,  deviation  of  the,  377. 

error  of  the,  377. 

variation  of  the,  377. 
Composition  of  anthracite  coal,  511. 
Compositions  and  alloys,  616. 
Compound,  535. 

engines,  109. 
Compressibility,  503. 
Compression,  264. 
Condensation,  503. 

Condenser  and  air-pump,  independent, 
345. 

Injector,  the,  344. 
Condensers,  338. 
jet,  340. 
surface,  340. 
Condensing  and  non-condensing,  econ- 
omy in  modern  steam-engines,  107. 
Condensing-engines,  steam-pumps  for, 
403. 

over  the  non-condensing  engine,  econ- 
omy of  the,  107. 
Conductibility,  503. 


EX.  675 

Conductors'  signals,  394. 
Conic  section,  51. 
Connecting-pipes,  476. 

rod,  piston,  and  crank  connections, 
175. 

Contents  of  an  elliptic  or  oval  tank  in 
cubic  feet  or  gallons,  rule  for  finding, 
523. 

Cooling  of  liquids  and  solids,  510. 

surface  in  tubes  of  surface  condensers, 
rule  for  finding,  343. 
Copper,  615. 
Corliss  engine,  Atlas,  663. 

Centennial,  25. 

Harris,  95. 

Reynolds,  177. 

Wetherill,  583. 
Corrosion,  and  its  analogy  to  combus- 
tion, 460. 

external,  460. 

internal,  460. 
Counter  has  been  working  into  minutes, 

to  reduce  the  time  the,  368. 
Counterbore,  160. 
Course,  376. 

made  good,  376. 

magnetic,  376. 

true,  376. 
Crab-claw,  229. 
Crank,  the,  183. 

base  of  the,  185. 

connections,  piston,  and  connecting- 
rod,  175. 
pins,  185. 

Crank-shaft  journals  and  main-bearings, 
187. 

to  determine  the  diameter  of  the,  135 
Cranks  of  steam-engines  to  their  shafts, 

fitting  the,  137. 
Cross-head  bearings,  181. 
Crown-bars,  476. 

braces,  477. 

sheet,  476. 

Cubical  contents  of  a  triangular  tank, 

rule  for  finding,  524. 
Curvilinear  seams,  462. 
Cushion,  264. 

Cut-oft*  and  throttling  engines,  automatic, 
130. 

an  adjustable,  227. 
a  positive,  227. 

engines,  automatic,  diagrams  taken 

from,  278. 
independent,  227. 


676 


INDEX. 


Cut-off,  riding,  227. 

to  equalize  the,  208. 
Cut-offs,  steam-engine,  132. 
Cylinder-boilers,  rule  for,  453. 

efficiency,  264. 

head-bolts,  166, 
Cylinders,  steam,  164. 
Cylindrical  steam-boilers,  bursting  press- 
ure of,  448. 

Daily  average  number  of  gallons  of  water 
used  per  individual  in  different 
cities,  table  showing,  524. 

Dashers,  477. 

Dash-pot,  228. 

Days  in  different  countries,  length  of,  382. 
Dead-centre,  the,  152. 

plate,  477. 

reckoning,  377. 

weight  safety-valves,  469. 
Decimal  arithmetic,  560. 
Declination,  377. 

Definition  of  technical  terms  applied  to 

different  kinds  of  boiler-plate,  486. 
Detuiitions  of  central,  mechanical,  and 

dynamical  forces,  587. 
Deflector,  477. 
Degrees  of  longitude,  379. 
Departure,  377. 

taking  a,  377. 
Design  of  steam-engines,  134. 
Deterioration  of  steam-boilers,  460. 
Deviation  of  the  compass,  377. 
Diagram,  theoretical,  279. 
Diagrams,  analysis  of,  271. 

indicator,  262,  291-320. 
Diagrams  taken  from  automatic  cut-off 

engines,  278. 
Diameter  of  the  crank-shaft,  to  deter- 
mine the,  135. 
Diameters  and  areas  of  small  circles, 

table  of,  543. 
Diaphragm-plate,  477. 
Difference,  378. 

of  longitude,  380. 
Different  parts  of  steam-engines,  techni- 
cal terms  applied  to,  160. 
terms  formerly  applied  to,  but  which 
have  become  obsolete,  161. 
Diffusion  of  vapor,  502. 
Dip  of  the  horizon,  378. 
Directions  for  operating  Sellers'  non-ad- 
justable fixed-nozzle  injector,  414. 
for  using  Eclipse  injector,  425. 


Displacement,  264. 
Distance,  377. 

polar,  377. 

zenith,  382. 
Dome,  477. 

stays,  477. 
Double-acting  air-pump,  356. 

beat  valves,  228. 
Douglas  automatic  cut-off  engine,  159. 
Draught  in  chimneys,  469. 
Draw  fires,  462. 

Duplicating  the  parts  of  steam-engines, 

136. 
Duty,  261 

Dynamical,   central,  and  mechanical 

forces,  definitions  of,  587. 
Dynamics,  589. 

Ebullition,  503. 
Eccentric,  the,  182. 

angular  advance  of  the,  183. 

back,  183. 

fore,  182. 

throw  of  the,  183. 
Eclipse  injector,  424. 

directions  for  using,  425. 
Ecliptic,  378. 

Economy  in  modern  steam-engines,  con- 
densing and  non-condensing,  107. 
of  high-pressure  engines,  131. 
of  the  condensing  over  the  non-con- 
densing engine,  107. 
steam-engine,  325. 
theoretical,  286. 
Effect  of  size  on  speed  of  steam-vessels, 
400. 

Effects  of  heat  upon  different  bodies, 

table  showing,  508. 
Efficiency,  cylinder,  264. 
Ejf  ctor  or  lifter,  the,  434. 
Elastic  fluids,  589. 
Elasticity,  590. 
Emergencies,  584. 
Energy,  590. 

Engine,  Atlas  Corliss,  286. 

condensing  over  the  non-condensing, 

economy  of  the,  107. 
high-pressure,  waste  in  the,  103. 
how  to  reverse  an,  145. 
in  line,  how  to  put  an,  141. 
low-pressure  or  condensing,  waste  in, 

104. 

Porter-Allen  high-speed,  330, 
surface-condensing,  355, 


INDEX. 


677 


Engine,  Woodbury,  Booth  &  Pryor  auto- 
matic cut-off,  52 
Woodruff  &  Beach  automatic  cut-off 
►         high-pressure,  124. 

Wright's  automatic  cut-off,  38. 
Engineer,  first  assistant,  58. 
Engineering,  steam,  27. 
Engineers,  facts  that  should  be  borne  in 
mind  by,  34. 
in  the  U.  S.  Navy,  necessary  qualifica- 
tions of  candidates  applying  for  ap- 
pointments as  cadets,  40. 
licensing,  30. 
locomotive,  62. 

qualifications  of  stationary,  60. 
questions  for,  99. 
Engines  and  boilers,  valves  and  cocks 
connected  with,  229. 
automatic  cut-off  and  throttling,  130. 
automatic  cut-off,   diagrams  taken 

ft-om,  278. 
Centennial  Corliss,  25. 
compound,  109. 

high-pressure,  economy  of.  131. 

marine,  113. 

simple,  112. 

speed  of,  118. 

throttling,  131. 
Equation  of  time,  382. 
Equator,  378. 
Equivalents,  535. 
Error  of  the  compass,  377. 
Estimating  the  power  of  steam-engines, 
118. 

Evaporation,  535. 
Evaporization,  503. 
Examination  for  assistant  engineer  in 
the  U.  S.  revenue-cutter  service,  58. 

in  arithmetic,  43. 

in  geography,  47. 

in  grammar,  42. 

in  natural  philosophy,  49. 

of  candidates,  40. 
Examinations  for  the  mercantile  marine 

service,  59. 
Exhaust-  and  steam-pipes,  180. 

to  equalize  the,  210. 
Expansion,  503. 

valve-gear,  227. 
Experiments  on  iron  plates  for  steam- 
boilers,  tabic  deduced  from,  623. 
Explosions,  steam-boiler,  464. 

Face,  valve,  218. 
57^ 


Facts  that  should  be  borne  in  mind  by 
engineers.  34. 

steam  users.  650. 
Fastening  leather  to  iron,  china,  or  glass. 

cement  for,  636. 
Feed-pump  pet-cock,  405. 

ram,  rule  to  find  diameter  of,  404. 
Feed-pump  for  condensing-engines,  40o: 
Feed,  to  reduce  the,  428. 
Feed -water  heaters^  474. 

temperature  of,  417. 
Fire,  506. 

Fire-engine,  the  steam,  120, 
Fires,  bank,  462. 

draw,  462. 

slice,  462. 

start,  462. 

Firing,  manual  and  mechanical,  461. 

technical  terms  applied  to.  462. 
First  assistant  engineer.  58. 
Fitcliburg  steam-engine  company  s  auto^ 

matic  cut-off  engine,  647. 
Fitting  the  cranks  of  steam-engines  to 

their  shafts,  137. 
Fittings  of  marine-boilers,  448. 
Fixed,  535. 
Flame,  506. 
Flexure,  264. 
Flue-boilers,  rule  for,  453. 
Fluids  and  vapors,  technical  terms  ap- 
plied to,  502. 
elastic,  589. 
Fly-wheels,  192. 

of  steam-engines,  rule  for  finding  pro- 
per weight  of,  193. 
Foaming  in  marine-boilers,  457. 
Focus,  591. 
Force,  590. 

of  wind  at  different  velocities,  table 
showing,  499. 
Fore  eccentric,  182. 

Formula  for  finding  horse  power  of 
steam-engines  by  indicator  diagrams, 
318.  319. 

for  finding  theoretical  clearance  when 
the  scale  is  known.  316 

for  finding  the  scale  of  a  diagran] 
when  clearance  is  known,  317. 
Friction,  59. 

of  riveted  seams,  463. 

of  slide-valves,  221. 

rollers.  591. 
Friedman's  injector,  420. 

table  of  capacities  of,  422. 


678 


INDEX. 


Fuel,  503. 

Functions  of  indicator,  261. 
Funnels,  472. 
Fusible  metal,  619. 

Gab-lever,  161. 
Gases,  530. 
Gasket,  477. 
Gauge-cocks,  477. 
Gauges,  mercury,  369. 

spring,  369. 
.  siphon,  369. 

vacuum,  369. 
Gearing,  645. 

Geography,  examination  in,  47. 
Geometry  and  trigonometry,  46. 
Gibs,  keys,  and  straps,  188. 
Gitiard  injector,  invention  of,  407. 
Governors,  steam-engine,  197. 
Grammar,  examination  in,  42. 
Grate-surface,  462. 
Gravity  and  gravitation,  592. 

centre  of,  589. 

specific,  592. 
Green  automatic  cut-ofif  high  -  pressure 

engine.  150. 
Gridiron-valves,  228. 
Grummet,  477. 
Gun-metal,  615. 
Gyration,  the  centre  of,  593. 

jSancock  inspirator,  table  of  capacities 
of  432. 

Harris  Corliss  steam-engine,  95. 
Heat,  507. 
latent.  507. 
of  steam,  64.- 
latent,  65. 
unit  of,  562. 
Heat-conducting  properties  of  different 

metals,  table  showing,  614. 
Heating  in  journals  and  reciprocating 

parts  of  steam-engines,  202, 
Heating  -  surface  of  tire-box  boilers  — 
locomotive,  marine,  or  stationary  — 
rule  lor  finding.  452. 
of  vertical  tubular-boilers,  such  as  are 
generally  used  for  fire-engines,  rule 
for  finding,  453. 
Higliest  mountains,  altitude  of,  in  the 
world.  500. 
waterfalls  in  the  world.  500. 
High-pressure  engine.  Greene,  150. 
valveless  engine,  Wardwell  s,  240. 


High-pressure  engine,  waste  in  the,  103. 
Woodruff  &  Beach  automatic  cut-off, 
24. 

High-pressure  engines,  economy  of,  131.  • 
High-speed  engine,  Porter-Allen,  330. 
Horizon,  dip  of  the,  378. 

visible,  378. 
Horse-povFer  for  different  piston-speeds, 
table  of  units  of,  170. 
Indicated,  266. 

to  calculate,  285. 
net,  266. 

of  steam-engines,  formulse  for  finding, 

by  indicator  diagrams,  318. 
of  waterfalls,  rule  for  finding,  523. 
of  wind-storms,  499. 

rule  for  finding,  500. 
or  power  of  a  horse,  593. 
Hotwell  thermometer,  the,  366. 
Hour-angle  of  a  celestial  object,  378. 
Housing,  164. 

Housings  and  bed-plates,  163. 
How  to  attach  the  indicator,  268. 

balance  reciprocating  and  revolving 
parts  of  vertical  engines,  202. 

calculate  theoretical  rate  of  water  con- 
sumption, 288. 

how  to  determine  the  amount  of  lap 
and  lead  on  a  valve  without  opening 
the  steam-chest,  218. 

increase  the  power  of  steam-engines, 
118,  148. 

keep  pipes  and  pumps  from  freezing, 
405. 

make  a  good  adhesive  cement,  636. 

make  belts  run  on  the  centre  of  pul- 
leys, 641. 

measure  a  coil  of  belting,  644. 

operate  the  inspirator,  431. 

put  an  engine  in  line,  141. 

put  on  a  belt,  644. 

repair  steam-engines,  146. 

reverse  an  engine,  145. 

set  up  a  stationary  engine,  143. 

set  valves  of  steam-engines,  224. 

test  the  quality  of  leather  for  belting. 
641. 

use  a  salinometer,  361. 
H.  P.,  265. 
H.  F.Cyl,,  265. 
Hydrodynamics,  593. 
Hydrogen,  532. 
Hyperbola,  265,  594. 
Hyperbolic  logarithms,  table  of,  557. 


INDEX . 


679 


Impact,  594. 
Impenetrability,  594. 
Impetus,  595. 
Incidence,  595. 
Inclination,  595. 
Inclined  plane,  595. 
Independent  air-pumps.  355. 

condenser  and  air-pump.  345. 

cut-off,  227. 

marine  circulating-pump,  358. 
Indicated  horse-power,  266. 

to  calculate,  285. 
Indicator  cards,  262. 
Crosby,  258. 
diagrams,  262,  291-320. 

show  what,  and  how,  321. 
functions  of,  261. 
how  to  attach  the,  268. 
steam-engine:  its  invention  and  im- 
provement, 258. 
technical  terms  used,  263. 
Inertia,  596. 
Initial  pressure,  266. 

or  steam-line,  282. 
Iiyection -water  required  to  condense  a 
certain  volume  of  steam,  relative 
quantity  of,  342. 
Injector,  clipper,  426. 

table  of  capacities  of,  ^28. 
condenser,  344. 
Eclipse,  424. 
Friedman's,  420. 
Keystone,  422. 

lifting,  423. 
method  of  starting  the,  434. 
Rue's  "  Little  Giant,"  418. 
to  start  the,  423. 

with  lifting  attachment  for  stationary 
boilers,  Sellers'  non-adjusting  fixed- 
nozzle,  412. 

\Vm.  Sellers  &  Co.'s,  408. 
Injectors,  406. 

Instructions  for  setting  up,  properly  at- 
taching, and  adjusting,  432. 
Inspirator,  430. 

Hancock,  table  of  capacities  of,  432. 
how  to  operate  the,  431. 
instructions  for  setting  up,  properly  at- 
taching, and  adjusting  injectors,  432. 
the  care  and  management  of  steam- 
boilers,  478. 
the  care  of  steam-engines,  235. 
Intercepter  or  separator,  473. 
Internal  strain  to  which  boilers  are  sub- 


jected when  under  pressure,  rule  for 

finding,  451. 
Invention  of  Giffard  injector,  407. 
Isothermal,  265. 

Jacket,  steam,  66. 

Jamison *s  steam  water-ejector,  435. 

table  of  capacities  of,  435. 
Jam -nuts,  160. 
Jet  condensers,  340. 

Journals  and  reciprocating  parts  of 
steam-engines,  heating  in,  202. 

Keys,  gibs,  and  straps,  188. 
Keystone  injector,  422. 

lifting  injector,  423. 
Knees,  478. 

Lacquer  for  brass  castings,  619. 
Lamps,  signals  by,  394. 
Lane  spring  steam-gauge,  369. 
Lap  and  lead  on  a  valve  without  opening 
the  steam-chest,  how  to  determine 
the  amount  of,  218. 
on  the  valve,  217. 
Latent  heat,  507. 
of  steam,  65. 

of  various  substances,  table  showing 
the,  508. 
Latitude,  378. 

and  longitude  of  places,  table  of,  384. 
Lead,  loss  of,  217. 

on  the  steam  end,  217. 

on  the  valve,  317. 
Leather  belting,  cement  for,  636. 
Leeway,  379.  * 

Length  of  days  in  different  countries, 
382. 

of  stroke  and  number  of  revolutions  for 
different  piston  -  speeds  in  feet  per 
minute,  table  showing,  172. 
unit  of,  562. 
Letter  b,  264. 
Letter  T,  268. 
Levers,  596. 

spring,  229. 
Lexicon  of  definitions  of  central,  me- 
chanical, and  dynamical  forces,  587. 
Licensing  engineers,  30. 
Lifter  or  ejector,  the,  434. 
Lifters,  229. 

Lift  of  safety-valves,  467. 
Lifting  and  stationary  links,  192. 
injector,  the  Keystone,  423. 


680 


INDEX, 


Light  signals  for  ocean  steamships,  390. 
Line  and  line,  204. 

Linear  dilatation  of  solids  by  heat,  table 
showing,  622. 

expansion  of  wrought-iron;  621. 
Link,  the.  189. 

radius  of  the.  191. 
Link-motion,  the,  189. 

Walschaert,  191. 
Links,  lifting  and  stationary,  192. 
Liquids  and  solids,  cooling  of,  510. 
"  Little  Giant    injector.  Rue's,  418. 
Location  of  steam-engines,  329. 
Lock  safety-valves,  469. 
Locomotive,  119. 

(engineers,  62. 

power  of  the,  119. 
Logarithms  of  numbers  from  0  to  1000, 

table  of,  555. 
Longitude,  379. 

degrees  of,  379. 

difference  of,  380. 

into  time,  to  reduce,  379. 
Longitudinal  seams,  462. 
Loss  of  lead,  217. 

Low  -  pressure  or  condensing  engine, 

waste  iu  the,  104. 
L.  P.  cyl.,  265. 
Lubricants,  243. 

Machines,  597. 

Magnetic  course.  376. 

Magnitudes  and  velocities  of  planets, 

table  showing,  375. 
Main-bearings  and  crank-shaft  journals, 

187. 

Manual  and  mechanical  firing,  461. 
Marine  bell-signals,  390. 

boilers,  fittings  of,  448 
foaming  in,  457 

circulating-pump,  independent,  358. 

engine,  113. 

signals,  386. 

steam-engine  register,  367. 

whistle-signals,  389. 

wrecking-pump,  359. 
Marine  engines,  reversing-gear  for,  203. 

uncertainty  of  tests  made  for  the  pur- 
pose of  comparing  the  relative  econ- 
omy of,  116. 
Mariner's  compass,  the,  373. 
Martin's  upright  tubular  boiler,  446. 
Materials,  boiler,  480. 
Mean  effective  pressure.  266,  283. 


Mean  speed  of  a  steam-vessel,  to  find,  400. 
time.  381. 

Measurement  of  screw-propeller,  395. 
Measures  and  weights.  610. 
Mechanical  and  manual  firing,  461. 

dynamical,  and  central  forces,  defini- 
tions of,  587. 
Mechanics,  598. 

Mercantile  marine  service, examinations 

for  the,  59. 
Mercury-gauge,  369. 
Meridian,  380. 

altitude,  376. 
Metal,  Babbitt's,  616. 

fusible.  619. 
Metals  and  alloys,  612. 
Method  of  starting  the  injector,  434. 
Mile  as  measured  by  various  nations,  table 
of,  382. 

Miles  and  knots,  knots  and  miles,  table 
of,  386. 

Millstones,  speed,  power,  capacity,  and 

dress  of,  632. 
Mineral  substances  and  their  chemical 

equivalents,  table  of,  612. 
Modulus,  600. 
Molecules  and  atoms,  566. 
Momentum,  600. 

Most  accurate  methods  of  testing  the  ad- 
justments, 274. 
Motion,  601. 

of  the  paper  drum,  262. 

perpetual,  604. 
Movers,  prime,  606. 
Multiplication,  peculiarities  of,  560. 
Muntz  metal,  615. 

Natural  philosophy,  examination  in,  49. 

Navigation,  technical  terms  and  defini- 
tions used  in,  376. 

Necessary  quantity  of  water  per  min- 
ute for  any  engine,  rule  for  finding 
404. 

Net  horse  power,  266. 
Neutral,  535. 
Neutralization,  535. 
Nitrogen,  531. 

Non-condensing  engine,  economy  of  the 
condensing  over  the,  107. 

Non-conducting  covering   for  steam- 
boilers  and  pipes,  634. 
properties  of  di  fferent  materials  at  even 
thickness,  table  showing,  510. 

Number  of  square  feet  of  heating-surface 


INDEX. 


681 


in  a  tube,  or  any  number  of 
rule  for  finding,  452. 

Observed  altitude,  376. 
Ordinates,  265. 

to  space  the,  285. 
Oscillation,  centre  of,  603. 
Over-stroke,  119. 
Oxidation,  535k 
Oxide,  535. 
Oxygen,  531. 

Paddle-vrheel,  396. 
Paper  drum,  motion  of,  269. 
Parallax,  380. 
Parallelism,  265. 
Parallels,  378. 

Parts  of  steam-engines,  duplicating  the, 
136. 

Peculiarities  of  multiplication,  560. 
Pendulum,  603. 

Percentage  of  loss  induced  by  blowing 
off  to  prevent  saturation,  rule  for 
finding,  364. 
Percussion,  603. 
Perpetual  motion,  604. 
Pet-cock  feed-pump,  405. 
Phosphate,  535. 
Pins,  crank,  185. 
Pipe  diagram,  266. 

swivel,  161. 
Pipes,  231. 

and  pumps  from  freezing,  how  to  keep, 
405. 

Piston  air-pump,  356. 

connecting-rod,  and  crank  connec- 
tions, 175. 

rod  and  valve-rod  packing,  and  how 
to  use  it,  237. 

rods,  169. 
Pistons,  steam,  167. 
Pitman,  161. 
Plane,  the  inclined,  595. 
Planimeter,  the,  323  656. 
Plate,  wrist,  229. 
Plug-tree,  161. 
Plunger  air-pump,  356. 
Pneumatics,  605. 

Points  of  the  compaiss,  table  of  rhumbs, 

or,  374. 
Polar  distance,  377. 
Poles,  380. 

Porter-Allen  high-speed  engine,  330. 
Port  side,  380. 


;,    Positive  cut-off,  227. 
Power,  606. 

and  speed  of  steam-vessels,  relation 

between,  399. 
of  a  horse,  593. 
of  the  locomotive,  119. 
of  steam-engines,  117. 
estimating  the,  118. 
how  to  increase  the,  118. 
required  to  raise  water  to  different  al- 
titudes varying  from  1  foot  to  20,000 
feet,  table  showing,  522. 
Practical  limits  to  thickness  of  boiler- 
plates, 485. 
Pressure,  606. 

and  temperature  of  vapors  of  water 
from  32°  to  400°  Fah.,  table  showing, 
526. 

mean  effective,  266,  283. 

of  a  diagram  from  its  area,  324. 
on  slide-valves,  rule  for  finding  the,  222. 
per  sq.  in.  of  sectional  area  in  crown- 
sheets  of  steam-boilers,  rule  for  find- 
ing, 451. 
safe-working,  462. 
terminal,  266. 
unit  of,  564. 
Prime  movers,  606. 
Priming,  458. 

Proper  number  of  revolutions  per  minute 
of  any  sized  saw,  rule  for  finding,  632. 
Proportion  of  carbon  in  various  grades 
of  iron  and  steel,  table  showing,  615. 
Proportions  of  the  United  States  or  Sel- 
lers' standard  threads  for  screws, 
nuts,  and  bolts,  table  giving  the,  631. 
Pulley,  the,  607. 

Pulleys  for  governors,  rules  for  calculat- 
ing the  size  of,  201. 
Pump-plunger  for  any  engine,  rule  for 

finding  diameter  of,  403. 
Pumps,  401. 
air,  353. 

Putnam  machine  company's  automatic 

cut-ott'  engine,  138. 
Pyrites,  536. 

Qualifications  of  candidates  for  the  U. 
S.  revenue  service,  57. 
stationary  engineers,  60. 
Quantity  and  weight  of  water  in  pipes  1 
fathom  in  length  (6  feet),  and  of  dif- 
ferent diameters  from  1  to  12  inches 
518. 


682  iNjy 

Quantity  of  water  per  lineal  foot  in 
pumps,  or  vertical  pipes  of  different 
diameters.  519. 
of  water  which  any  square  or  rectan- 
gular box  or  tank  is  capable  of  con- 
taining in  cubic  feet  or  U.  S.  gallons, 
rule  for  finding,  524. 

Questions  for  engineers,  99,  162,  246,  334, 
436,  491,  585,  668. 

Radiating  properties  of  different  sub- 
stances, table  showing,  508. 

Radius-bar,  161. 

Radius  of  the  link,  191. 

Railroad  signals,  391. 

Reciprocating  and  revolving  parts  of 
vertical  engines,  how  to  balance,  202. 

Reckoning,  dead,  377. 

Refraction,  380. 

Register,  marine  steam-engine,  367. 
Relation  between  power  and  speed  of 

steam-vessels,  399. 
Relative  economy  of  marine  engines, 

uncertainty  of  tests  made  for  the 

purpose  of  comparing  the,  116. 
quantity  of  injection-water  required  to 

condense  a  certain  volume  of  steam, 

342. 

volumes  of  air  at  various  temperatures, 

table  showing  the,  501. 
weight  and  volume  of  different  gases, 
table  showing,  508. 
Release,  265. 
Releasing  valve-gear,  226. 
Relief-valves,  228. 

Remedies  for  knocking  in  steam-engines, 
155. 

Resilience,  608. 

Results  of  experiments  made  on  different 
brands  of  boiler-iron  at  the  Stevens 
Institute  of  Technology,  620. 

Rev.  or  Revs.,  266. 

Reversing-gear  for  marine  engines,  203. 

valve-gear,  227. 
Revolutions  engine  has  made  during 
voyage,  rule  for  finding  number  of, 

368. 

Revolving  shafts,  how  to  prevent  acci- 
dents by,  643. 
Reynolds  Corliss  engine,  177. 
Riding  cut-off,  227. 
Right  a.scension.  381. 
Riveted  seams,  friction  of,  463. 
Rock-shafts,  181. 


Rods,  air-pump,  357. 
piston,  169. 
valve,  182. 
Rollers,  friction,  591. 
Rolling  circle  of  a  wheel.  398. 
Rotary-valves,  228. 
Rubber  and  leather  belts,  642. 

belting,  cement  for,  637. 
Rue's  "  Little  Giant"  injector,  418. 

table  of  capacities  of,  420. 
Rule  for  cylinder-boilers,  453. 
Rule  for  finding  aggregate  strain'  caused 
by  pressure  of  steam  on  shells  of 
boilers,  451. 
amount  of  gain  derived  from  working 

steam  expansively,  67. 
approximate  weight  of  iron  castings 

from  patterns,  619. 
bursting  pressure  of  cylindrical  boilers 

with  riveted  seams,  448. 
centre  of  gravity  of  taper-levers,  for 

safety-valves,  469. 
change  required  in  length  of  belt  when 
one  of  the  pulleys  on  which  it  runs 
is  changed  for  one  of  different  size, 
644. 

collapsing  pressure  of  boiler-flues,  452. 

contents  of  an  elliptic  or  oval  tank  in 
cubic  feet  or  gallons,  523. 

cooling  surface  in  tubes  of  surface  con- 
densers, 343. 

cubic  contents  of  a  steam-cylinder.  166. 

cubical  contents  of  a  triangular  tank, 
524. 

diameter  of  a  driven  pulley  for  a  given 
number  of  revolutions,  645. 

diameter  of  a  pinion  when  the  diame- 
ter of  the  driver  and  the  number  of 
teeth  in  driver  and  pinion  are  given, 
645. 

diameter  of  pump-plunger  for  any  en- 
gine, 403. 

diameter  of  toothed  wheels.  645. 

distance  piston  is  ahead  of  a  central 
position  in  the  cylinder,  176. 

heating  surface  of  fire-box  boilers,  etc.. 
452. 

heating  surface  of  vertical  tubulau 
boilers,  453. 

horse-power  of  a  locomotive,  120. 

horse-power  of  a  steam-engine  by  in- 
dicator diagrams.  121. 

horse-power  of  simple  condensing  en- 
gine.s,  121. 


IND 

Rule  for  finding  horse-power  of  steam- 
engines  and  fire-engines,  120. 

horse-power  of  waterfalls,  523. 

horse-power  of  wind  storms,  500. 

internal  strain  to  which  boilers  are 
subjected  when  under  pressure,  451. 

mean  or  average  pressure  in  cylinder 
of  a  steam-engine,  68. 

necessary  quantity  of  water  per  minute 
for  any  engine,  404. 

n'amber  of  revolutions  engine  has 
made  during  voyage,  368. 

number  of  revolutions  in  each  wheel 
for  a  train  of  spur-wheels,  646. 

number  of  revolutions  of  a  driver,  646. 

number  of  revolutions  of  the  last  wheel 
in  a  train  of  wheels  and  pinions, 
spurs  or  bevels,  646. 

number  of  square  feet  of  heating  sur- 
face in  a  tube  or  any  number  of 
tubes,  452. 

percentage  of  loss  induced  by  blowing 
off  to  prevent  saturation,  364. 

point  of  cut-off  required  to  produce  a 
given  terminal  from  a  given  initial 
pressure,  221, 

point  of  cut-off  when  the  initial  and 
mean  pressure  are  known,  221. 

pressure  at  which  a  safety-valve  is 
weighted  when  length  of  lever, 
weight  of  ball,  etc.,  are  known,  468. 

pressure  per  square  inch  of  sectional 
area  or  crown-sheets  of  steam-boil- 
ers, 451. 

pressure  per  square  inch  when  area  of 
valve,  weight  of  ball,  etc.,  are  known, 
468. 

proper  number  of  revolutions  per  min- 
ute of  any  sized  saw,  632. 

proper  thickness  for  steam-cylinders, 
165. 

proper  weight  of  fly-wheels  of  steam- 
engines,  193. 

quantity  of  steam  any  engine  will  use 
at  each  stroke  of  the  piston,  166. 

quantity  of  water  which  any  square  or 
rectangular  box  or  tank  is  capable 
of  containing  in  cubic  feet  or  U.  S. 
gallons,  524. 

required  area  for  chimneys  of  station- 
ary boilers,  473. 

required  diameter  of  cylinder  for  an 
engine  of  any  given  horse-power, 
165. 


EX.  683 

Rule  for  finding  required  number  of  teeth 
in  a  pinion  to  have  any  given  veloc- 
ity, 645. 

required  size  of  a  driving-pulley  for 

any  required  speed,  644. 
safe  external  pressure  on  boiler- flues, 

452. 

safe  working-pressure  of  iron  boilers, 
451. 

strain  due  to  pressure  of  steam  on  boil- 
er-stays, 452. 

strain  exerted  in  a  longitudinal  direc- 
tion by  pressure  of  steam  in  a  boiler, 
449. 

•  strain  exerted  in  a  transverse  direction 
by  pressure  of  steam  in  a  boiler,  449. 

strength  of  single-  or  double-riveted 
seams,  452. 

weight  necessary  to  put  on  a  safety- 
valve  lever,  4C8. 

width  of  belt  to  transmit  a  given  horse- 
power, 643. 
Rule  for  flue-boilers,  453. 

tubular-boilers,  453. 
Rule  to  find  area  of  a  circle,  538. 

a  cycloid,  539. 

an  ellipse,  539. 

an  elliptic  segment,  539. 

an  hyperbola,  540. 

an  oval,  538. 

any  polygon,  539. 

parallelogram,  538. 

quadrilateral  inscribed  in  a  circle,  539. 

regular  polygon,  539. 

sector  of  a  circle,  539. 

segment  of  a  circle,  539. 

trapezoid,  539. 

triangle,  538. 

circumference  of  a  circle,  538. 
circumference  of  an  ellipse  or  oval, 
538. 

curve  surface  of  any  segment  or  zone 
of  a  sphere,  541. 

cubic  contents  of  a  frustum  of  a  para- 
bolic conoid,  541. 

cubic  contents  of  a  frustum  of  a  pyra- 
mid or  a  cone,  540. 

cubic  contents  of  a  frustum  or  zone  of 
a  sphere,  541. 

cubic  contents  of  a  parabolic  conoid, 
541. 

cubic  contents  of  a  prism  or  a  cylinder, 
540. 

cubic  contents  of  a  prismoid,  541. 


684 


INDEX. 


Rule  to  find  cubic  contents  of  a  pyramid 
or  a  cone,  540. 
cubic  contents  of  a  segment  of  a  sphere, 
540. 

cubic  contents  of  a  segment  of  a  sphe- 
roid, 541. 

cubic  contents  of  a  sphere,  541. 
"         "        *'   wedge,  541. 

diameter  of  a  circle,  538. 

diameter  of  feed-pump  ram,  404. 

length  of  an  arc  of  a  hyperbola  begin- 
ning at  vertex,  540. 

length  of  an  arc  of  a  parabola  cut  off 
by  a  double  ordinate  to  the  axis,  539. 

surface  of  a  frustum  of  a  pyramid  or 
a  cone,  540. 

surface  of  a  prism  or  a  cylinder,  540. 

surface  o.f  a  pyramid  or  cone,  540. 

surface  of  a  sphere,  541. 
Rules  for  calculating  number  of  horse- 
powers a  belt  will  transmit,  643. 

size  of  pulleys  for  governors,  201. 

comparing  degrees  of  temperature  in- 
dicated by  different  thermometers, 
366. 

for  finding  length  of  belt,  643. 
for  finding  pressure  on  slide-valves,  222. 
Rust,  613. 

Rust-joints,  cement  for,  635. 

Safe  external  pressure  on  boiler-flues,  rule 
for  finding,  452. 

working-pressure  of  iron  boilers,  rule 
for  finding,  451. 

working-pressure,  or  safe  load,  462. 
Safety-valves,  465,  654. 

dead-weight,  469. 

lift  of,  467. 

lock,  469. 

spring,  469. 
Sailing  distances  from  New  York  to  dif- 
ferent parts  of  the  world,  383. 
Saline,  5iJ6. 
Sali  no  meter,  360  650. 

how  to  use  a,  361. 
Salt  in  water  of  different  seas,  table  show- 
ing proportion  of,  362. 
Saturation,  363,  536. 
Scale,  267. 

in  steam-boilers,  455. 

of  a  diagram,  formula  for  finding,  317. 
Scoggin,  161. 
Screw,  607. 


Screw-propeller,  394. 

and  paddle-wheel,  comparative  effi- 
ciency of,  399. 

measurement  of,  395*. 
Scum-cocks,  478. 
Seams,  curvilinear,  462. 

longitudinal,  462. 
Seat-valve,  218. 
Sea-water,  analysis  of,  457. 
Section,  conic,  51. 

Sellers'  injectors,  table  of  capacities  of,  417. 

non-adjustable  fixed-nozzle  injector, 
directions  for  operating,  414. 

non-adjusting  fixed-nozzle  injector,412. 
Semi-diameter,  381. 

rotary  valves,  228. 
Shackle-bar,  161. 
Shafts,  rock,  181. 
Ship's  side  air-pump,  357. 
Shrinkage  of  castings  of  different  metals, 

table  showing,  620. 
Sidereal  time,  381. 
Signals  by  lamp,  394. 

conductors',  394. 

enginemen's,  393. 

for  ocean  steamships,  light,  390. 

marine,  386. 

railroad,  391. 

train,  392. 

Signification  of  signs  used  in  calcula- 
tions, 542. 

Signs  used  in  calculations,  signification 

of,  542. 
Simple  engines,  112. 
Slice  fires,  462. 
Slide-valve,  205. 
Slide-valves,  friction  of.  221. 

rule  for  finding  pressure  on,  222. 
Slip  of  the  screw,  395. 
Smoke,  473,  506. 
Snifting-valve,  341. 
Solder,  617,  619. 
Space,  water,  462. 
Spanner-guard,  478. 
Specific  gravity,  592. 

heat  of  different  substances,  table 
showing,  509. 
Spectacles,  478. 
Speed  of  circular-saws,  632. 

of  engines,  118. 

of  steam-vessels,  effect  of  size  on,  400. 
power,  capacity,  and  dress  of  mill- 
stones, 632. 


INDEX. 


686 


Spelling,  43. 
Spider,  161. 

Spontaneous  combustion,  512. 
Spring,  267. 

gauge,  369. 

levers,  229. 

safety-valves,  469.  * 
steam-gauge,  Bourdon,  370. 
Lane,  369. 

Squares,  cubes,  and  square  and  cube  roots 
of  all  numbers  from  1  to  620.  567. 

standard  of  examination  for  assistant 
engineer  in  U.  S.  revenue  cutter  ser- 
vice, 58. 

weights  of  cast-iron  gas-  and  water- 
pipes,  tables  showing,  628. 
Jtarboard  side,  381. 
Start  fires,  462. 
Star  ting- val^e  gear,  228. 
Statics,  608. 

Stationary  and  lifting  links,  192. 

engine,  how  to  set  up  a,  143. 

engineers,  qualifications  of,  60. 
Stay-bolts,  454. 

tubes,  477. 
Stays,  boiler,  453.  • 
Steam,  63. 

heat  of,  64. 

jacket,  66. 

latent  heat  of,  65. 

ports,  70. 

saturated,  63. 

surcharged,  63. 

temperature  of,  63. 

volume  of,  64. 
Steam-  and  exhaust-pipes,  180. 
Steam-boiler  explosions,  464. 
Steam-boilers,  442. 

and  pipes,-  non-conducting  covering 
for,  634. 

bursting  pressure  of  cylindrical,  448. 

cylinders,  164. 

deterioration  of,  460. 

scale  in,  455. 
Steam  end,  loss  on  the,  217. 
Steam-engine,  Brown  automatic  cut-off, 
88. 

cut-offs,  132. 
economy,  325. 
governors,  197. 
Harris  Corliss,  95. 
how  to  increase  power  of,  148. 
indicator,  251, 
58 


Steam  engineering,  27. 
Steam-engines,  causes  of  knocking  in, 
153. 

condensing  and  non-condensing,  econ- 
omy in  modern,  107. 

design  of,  134. 

duplicating  parts  of.  136. 

estimating  power  of,  118. 

fitting  thie  cranks  of,  137. 

heating  in  journals  and  reciprocating 
parts  of,  202. 

how  to  increase  power  of,  118. 

how  to  repair,  146. 

how  to  set  valves  of,  224. 

in  general,  102. 

instructions  for  care  of,  235. 

location  of,  329. 

power  of,  117. 

remedies  for  knocking  in,  155. 
Steam  fire-engine,  120. 
Steam-j  oints  and  patching  steam -iDoilers, 
cement  for.  634. 

line,  or  initial  pressure,  282. 

pistons,  167. 

pressure  required  to  lift  and  deliver 
water  with  Sellers'  fixed-nozzle  lift- 
ing-injector, table  showing,  412. 

room,  462. 

water-ejector,  Jamison's,  435. 
table  of  capacities  of,  435. 
Steel,  613. 
Stern-tube,  396. 
Stone  or  marble,  cement  for,  637. 
Strain  due  to  pressure  of  steam  on  boiler- 
stays,  rule  for  finding,  452. 
exerted  in  a  longitudinal  direction  by 

pressure  of  steam  in  a  boiler,  449. 
exerted  in  a  transverse  direction  by 

pressure  of  steam  in  a  boiler,  449. 
that  will  pull  different  metals  asunder 
on  a  straight  pull,  table  showing,  618. 
Straps,  keys,  and  gibs,  188. 
Strength,  609. 

of  copper  boiler-plates  at  different  tem- 
peratures, table  showing,  623. 
of  single-  or  double-riveted  seams,  rule 
for  finding,  452". 
String,  267. 
Stroke,  valve,  218. 
Sulphur,  615. 
Superheaters,  473. 
Surface  condensers,  340. 
condensing  engine,  355. 


686 


INDEX. 


Surface,  grate,  462. 

unit  of,  563. 
Syphon-gauge,  369. 

Table  containing  diameters,  circumfer- 
ences, and  areas  of  circles,  etc.,  544. 

deduced  from  experiments  on  iron 
plates  for  steam-boilers,  623. 

giving  proportions  of  U.  S.  or  Sellers'  j 
standard  threads  for  screws,  nuts, 
and  bolts,  631. 

of  altitudes  above  sea-level,  498. 

of  average  performances  of  different 
designs  of  pumping-engines.  114. 115. 

of  capacities  of  Clipper  injectors,  428. 

of  capacities  of  Friedman's  injectors, 
422. 

of  capacities  of  Hancock  inspirator,  432. 

of  capacities  of  Jamison's  steam  water- 
ejector,  435.  . 

of  Capacities  of  Rue's  "  Little  Giant" 
injector,  420. 

of  capacities  of  Sellers'  injector,  417. 

of  coefficients  of  frictions  between 
plane  surfaces,  633. 

of  common  and  decimal  fractions,  561. 

of  constant  numbers  by  which  to  as- 
certain the  average  of  the  steam 
against  the  piston,  etc  ,  69. 

of  constant  numbers  for  finding  the  re- 
quired "lap"  for  slide-valves,  etc.,  70. 

of  diameters  and  areas  of  small  circles, 
543.  T 

of  elastic  force,  temperature,  and  vol- 
ume of  steam,  etc.,  76-80.  , 

of  hyperbolic  logarithms,  68,  557. 

of  latitude  and  longitude  of  places,  384. 

of  logarithms  of  numbers,  etc.,  555. 

of  mile  as  measured  by  various  na- 
tions, 382. 

of  miles  and  knots,  knots  and  miles, 
386. 

of  mineral  substances  and  their  chem-  \ 

ical  equivalents,  612. 
of  multipliers,  etc.,  69. 
of  rhumbs,  or  points  of  the  compass, 

374. 

of  sailing  distances,  etc.,  in  geograph- 
ical miles,  383. 

of  squares,  cubes,  and  square  and  cube 
roots  of  numbers  from  1  to  620,  567. 

of  units  of  horse-power  for  different 
piston-speeds,  170. 


ble  of  vulgar  and  decimal  fractions  of 
an  inch,  561. 

showing  actual  extension  of  wrought- 
iron  at  various  temperatures,  621. 

showing  all  the  units  of  length  recog- 
nized in  England  since  the  16th  cen 
tury,  565.  * 

showing  amount  of  "lap"  required 
for  slide-valves,  etc.,  220. 

showing  average  crushing  load  of  dif- 
ferent materials,  617. 

showing  boiling-point  for  fresh  water 
at  different  altitudes  above  sea-level, 
520. 

showing  boiling-point  of  salt  water 
at  different  degrees  of  density,  etc., 
362. 

showing  breaking  strain  of  iron  and 

copper  stay-bolts,  455. 
showing  capacity  of  cisterns  and  tanks, 

521. 

showing  capacity  of  cisterns  in  gallons 
for  each  10  inch  depth,  523. 

showing  daily  average  number  of  gal- 
lons of  water  per  individual  in  dif- 

%  ferent  cities,  etc.,  524. 

showing  effect  of  heat  upon  different 
bodies,  508. 

showing  different  velocity  of  steam  at 
different  pressures,  etc.,  67. 

showing  force  of  wind,  etc.,  at  different 
velocities,  499. 

showing  force  of  uncondensed  steam, 
etc.,  according  to  temperature,  341. 

showing  heat-conducting  properties  of 
different  metals,  614. 

showing  increase  of  sensible  and  de- 
crease of  latent  heat  in  steam,  65. 

showing  latent  heat  of  various  sub- 
stances, 508. 

showing  length  of  stroke  and  number 
of  revolutions  for  different  piston- 
speeds  in  feet  per  minute,  172. 

showing  linear  dilatation  of  solids  by 
heat.  622. 

showing  magnitudes  and  velocities  of 
planets,  375 

showing  maximum  and  minimum  de- 
livery of  Sellers'  self-adjusting  in- 
jector, etc.,  416. 

showing  non  conducting  properties 
different  materials  at  even  thickness. 
510. 


INDEX. 


687 


Table  showing  power  required  to  raise 
water  to  different  altitudes,  etc.,  522. 
showing  pressure  and  temperature  of 
vapor  of  water  from  32^  to  400°  Fah., 
526. 

showing  proper  thickness  for  steam- 
cylinders  from  6  to  90  inches,  166. 

showing  proportion  of  carbon  in  the 
various  grades  of  iron  and  steel.  615. 

showing  proportion  of  salt  in  water  of 
different  seas,  362. 

showing  quantity  and  weight  of  water 
in  pipes  of  one  fathom  in  length  (6 
feet),  etc.,  518. 

showing  quantity  of  water  per  lineal 
foot  in  pumps,  or  vertical  pipe  of 
different  diameter,  519. 

showing  radiating  properties  of  differ- 
ent substances,  508. 

showing  relative  volumes  of  air  at  va- 
rious temperatures,  501. 

showing  relative  weight  and  volume 
of  different  gases,  509. 

showing  results  of  experiments  made 
on  different  brands  of  boiler-iron, 
630. 

showing  shrinkage  of  castings  of  dif- 
ferent metals,  620. 

showing  specific  heat  of  different  sub- 
stances, 509. 

showing  standard  weights  of  cast-iron 
water-  and  gas-pipes,  628. 

showing  steam-pressure  in  pounds  per 
gauge,  etc.,  85. 

showing  steam-pressure  required  to 
lift  and  deliver  water  with  Sellers' 
fixed-nozzle  lifting  injector,  412. 

showing  strain  that  will  pull  different 
metals  asunder  on  a  straight  pull, 
618. 

showing  strength  of  copper  boiler 
plates  at  different  temperatures,  etc., 
623. 

showing  temperature  and  weight  of 
steam  at  different  pressures,  etc., 
'81-84. 

showing  temperature  of  steam  at  dif- 
ferent pressures,  etc.,  74.  75. 

showing  tenacity  or  tensile  strength  of 
different  metals,  614. 

showing  tensile  strength  of  different 
kinds  of  wood.  618. 

showing  temperature  of  saturated  va- 


por in  atmosphere,  according  to 
Zeuner.  525. 
Table  showing  tensile  strength  of  various 
qualities  of  American  and  English 
cast-iron,  628. 
showing  'tensile  strength  of  various 
qualities  of  American  wrought-iron. 
629. 

showing  time  at  different  places,  385. 

showing  total  heat  of  combustion  of 
various  fuels,  512. 

showing  units  of  heat  required  to  con 
vert  1  pound  of  water,  at  tempera- 
ture of  32°.  into  steam  at  different 
pressures,  475. 

showing  vacuum  in  inches  of  mercury 
and  pounds  pressure  per  sq.  in.,  349. 

showing  weight  and  bulk  of  different 
substances  in  cubic  feet,  pounds,  and 
tons,  620. 

showing  weight  of  atmosphere  per 

sq.  in.  corresponding  with  differenc 

heights  of  barometer.  365. 
showing  weight  of  boiler-plates  1  foot 

square  and  from  one-sixteenth  of  an 

inch  to  an  inch  thick.  626. 
showing  weight  of  castings  by  weight 

of  the  patterns,  620. 
showing  weight  of  cast-iron  balls  from 

3  to  13  inches  in  diameter,  624. 
showing  weight  of  cast-iron  pipes,  etc., 

627. 

showing  weight  of  cast-iron  plates  per 
superficial  foot  as  per  thickness,  624. 

showing  weight  of  different  metals  per 
cubic  foot,  621. 

showing  weight  of  round  iron,  etc.,  625. 

showing  weight  of  square  bar-iron,  etc., 
620. 

showing  weight  of  water  at  different 
temperatures,  520. 

Tables  showing  average  pressure  of  the 
steam  upon  the  piston  throughout 
the  stroke,  etc.,  71-73. 

Taking  a  departure,  377. 

Technical  and  chemical  terms  that  bear 
relation  to  the  steam-engine,  534. 
terms  and  definitions  used  in  naviga- 
tion, 376. 

terms  applied  to  adjuncts  of  steam- 
boiler,  476. 

terms  applied  to  different  kinds  of 
boiler-plate,  486. 


688 


INDEX. 


Technical  terms  applied  to  different 

parts  of  steam-engines,  160. 
terms  applied  to  firing,  462. 
terms  applied  to  fluids  and  vapors,  502. 
terms  employed  in  relation  to  boilers, 

462. 

terms  used  in  connection  with  employ- 
ment of  indicator,  263. 
Temperature  of  feed-water,  417. 

saturated  vapor  in  atmosphere,  table 

showing,  525. 
of  steam,  63. 
Tenacity  or  tensile  strength  of  different 

metals,  table  showing,  614. 
Tensile  strength  of  different  kinds  of 
wood,  table  showing,  618. 
stren^h  of  various  qualities  of  Amer- 
ican cast-iron,  628. 
strength  of  various  qualities  of  Ameri- 
can wrought-iron,  629. 
Terminal  pressure,  266. 
Terms  formerly  applied  to  different  parts 
of  steam-engines,  but  which  have 
become  obsolete,  161. 
Theoretical  clearance  when  the  scale  is 
known,  formula  for  finding,  316. 
diagram,  279. 
economy,  286. 

rate  of  water  consumption,  how  to  cal- 
culate, 288. 
Theoretic  curve,  application  ot,  280. 
Tliermal  unit,  the,  507. 
Thermometer,  the  Hotwell,  366. 

the  Uptake,  366. 
Thermometers,  365. 

rules  for  comparing  degrees  of  temper- 
ature indicated  by  different,  366. 
Throttle-valves,  228. 
Throttling  and  automatic  cut-off  engines, 
130. 

engines,  131. 
Throw  of  the  eccentric,  183. 
Thrust-block,  395.  . 
Tighteners,  642. 
Time,  apparent,  381. 

astronomical,  381. 

at  different  places  at  noon,  New  York, 

table  showing,  385. 
civil,  381. 
equation  of,  382. 
mean,  381. 

or  duration,  unit  of,  564, 
sidereal,  381. 


To  calculate  the  indicated  horse-power, 
285. 

To  compromise  between  unequal  lead  and 

cut-off,  210. 
To  equalize  the  cut-off,  208. 

the  exhaust,  210. 
To  find  diameter  of  engine  shaft-pulley,  201. 
diameter  of  governor  shaft-pulley,  201. 
mean  effective  pressure  of  a  diagram 

from  its  area,  324. 
mean  speed  of  a  steam- vessel,  400. 
Tools,  609. 

To  reduce  longitude  into  time,  379. 
the  feed,  428. 

the  time  the  counter  has  been  working 
into  minutes,  368. 
Torsion,  609. 

To  space  the  ordinates,  285. 

start  the  injector,  423. 
Total  heat  of  combustion  of  various  fuels, 

table  showing,  512. 
Train  signal,  392. 
Trigonometry  and  geometry,  46. 
Trips,  229. 
Trophies,  381. 
True  altitude,  376. 

course,  376. 
Trunk,  161. 

air-pump,  356. 
Trunnions,  161. 
Tube-sheets,  478. 
Tubular-boilers,  rule  for,  45. 

Uncertainty  of  tests  made  for  the  pur- 
pose of  comparing  the  relative  econ- 
omy of  marine  engines,  116. 

Uncondensed  steam  arising  from  water 
in  condenser  resists  ascent  or  descent 
of  piston,  table  showing  force  with 
which,  341. 

Undulating,  268. 

Unequal  lead  and  cut-off,  to  compromise 

between,  210. 
Unit  of  capacity,  563. 

of  heat,  562. 

of  length,  562. 

of  pressure,  564. 

of  surface,  563. 

of  time  or  duration,  564. 

of  velocity,  564. 

of  weight,  563. 

of  work,  564. 

the  thermal,  507. 


INDEX. 


689 


Tnits,  562. 

of  heat  required  to  convert  1  pound 

of  water,  at  temperature  of  32°,  into 

steam  at  different  pressures,  475. 
of  length  recognized  in  England  since 

the  sixteenth  century,  table  showing, 

565. 

Upright  tubular-boiler,  Martin's,  446. 
Uptake  thermometer,  the,  366. 
U.  S,  revenue  service,  qualifications  of 
candidates  for  the,  57. 

Vacuum,  348. 
gauges,  369. 

in  inches  of  mercury  and  pounds 
pressure  per  square  inch,  table  show- 
ing, 349. 

Value,  comparative,  of  different  kinds  of 
wood  for  fuel,  505. 

of  wood  as  fuel  compared  with  coal, 504. 
Valve  circle,  218, 

face,  218. 
,  lap  on  the,  217. 
^  lead  on  the,  217. 

rods,  182. 

seat,  218. 

snifting,  341. 

stroke,  218. 
Valve.gear  and  valves,  226. 

automatic  cut-off,  217. 

expansion,  227 

releasing,  226. 

reversing,  227. 

whole-stroke,  227. 
Valve-rod  and  piston-rod  packing,  and 

how  to  use  it,  237. 
Valves  ana  cocks  connected  with  engines 
and  boilers,  229. 

and  valve-gear,  226. 

balance,  228. 

double-beat,  228. 

gridiron,  228. 

of  steam-engines,  how  to  set,  224. 

relief,  228. 

rotary,  228. 

safety,  465. 

semi-rotary,  228, 

throttle,  228. 
Vapor,  diffusion  of,  502, 
Vaporization,  502. 
Vapors,  525. 

Variation  of  the  compass,  377. 
Velocity,  610. 

58* 


Velocity,  unit  of,  564. 
Vertical  air-pump,  354. 

engines,  how  to  balance  reciprocating 

and  revolving  parts  of,  202. 
Visible  horizon,  378. 
Volume  of  steam,  64. 
Vulgar  and  decimal  fractions  of  an  inch 

table  of,  561. 

Walschaert  link-motion,  191. 
Wardvrell's  high-pressure  valveless  en- 
gine, 240. 
Waste,  478. 

in  the  high-pressure  engine,  103. 
in  the  low-pressure  or  condensing  en- 
gine,  104. 
Water,  514. 

consumption,  how  to  calculate  theo- 
retical rate  of,  288. 
space,  462. 

Water-falls,  highest,  in  the  world,  500. 
Watertown  automatic  cut-off  engine,  214. 
Wedge,  611. 
Weight,  610. 

and  bulk  of  different  substances  in 
cubic  feet,  pounds,  and  tons,  table 
showing,  620. 
of  atmosphere  per  sq.  in.  correspond- 
ing with  different  heights  of  barome- 
ter, 365. 

boiler-plates  1  foot  square  and  from 
one-sixteenth  of  an  inch  thick,  table 
snowing  the,  626. 
of  castings  by  weight  of  patterns,  table 

showing,  620. 
of  cast-iron  balls  from  3  to  13  inches  in 

diameter,  table  showing,  624. 
of  cast-iron  pipes,  1  foot  in  length,  etc., 

table  showing  the,  627. 
of  cast-iron  plates  per  superficial  foot 
as  per  thickness,  table  showing,  624. 
of  different  metals  per  cubic  foot,  table 

showing,  621. 
of  round  Iron  from  one-half  of  an  inch 
to  6  inches  in  diameter,  1  foot  long, 
table  showing,  625. 
of  square  bar-iron,  from  one-half  of  an 
inch  to  6  inches  square,  etc.,  table 
showing  the,  626. 
•    of  water  at  different  temperatures, 
table  showing,  520. 
unit  of,  563. 
Weights  and  measures,  610. 


690 


INDEX. 


Wells  two-piston  balance-engine.  232. 
Wetherill  Corliss  engine,  the,  583. 
What  iiidieator  diagrams  show,  and  how 

they  show  it,  321. 
Wheel  and  axle,  611. 

rolling  circle  of,  398. 
Wheelock  automatic  cut-off  engine,  214. 
Wheels,  fly,  192.  . 
Whistle-signals,  marine,  389. 
White  metal,  615, 
Whole-stroke  valve-gear,  227. 
Wind  storms,  horse-power  of,  499. 
Wire-drawing,  268. 


William  Sellers  &  Co.'s  injector,  408. 
Wood  as  fuel,  value,  compared  with,  504. 
Woodruff  &  Beach  automatic  cut-off 

high-pressure  engine,  124. 
Work,  611. 

unit  of,  564. 
Wrecking-pump,  marine,  359. 
Wright's  automatic  cut-off  engine,  38. 
Wrist-plate,  229. 

Wrought-iron,  linear  expansion  of,  62i 

Zenith  distance,  382. 
Zero,  268. 


THE 


ENJDo 


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